For the same reason that it opposes assisted dying. Suppose that you had made a claim that every statement coming from your mouth is the absolute truth, and suppose, further, that this claim is not only known by practically everyone in the world, but that millions, perhaps billions of people, believe you, and stake their lives on this belief. Now, suppose that you finally came to your senses, and realised that no one can make such a claim in good faith, and that you, like everyone else, is liable to error, to making judgements in haste and on poor evidence, and that some of your statements – statements that your followers have taken with the utmost gravity, and defended, basing their entire lives on them – seem now, in retrospect, to have consequences that you can no longer defend. What should you do?
While you’re thinking about that problem, remember all those people who trusted you, and genuinely believed that your claims, and the claims made on your behalf, that you could not err, were valid for all time; remember that their lives will suddenly be without the firm foundation upon which they believed they stood, that everything that they believed, everything they had ever published, all the protest movements in which they had participated, and all the shrill condemnations that they had uttered in your name, will be nullified in a second if you suddenly lose your nerve, and say that, after all, you were wrong.
But still, remember, if you will, that the consequences of your claims, and the claims made on your behalf, are not insignificant. Not only have many of your erstwhile followers concluded long ago that you were wrong, but believing that you were right all along has caused much distress. Many people have died in misery, because of your belief that helping them to die was opposed to all that was true and noble and good. Women, who might have lived full, happy lives, have died in misery, simply because you denied them the right to control their reproductivity, and in desperation have resorted to all sorts ineffective, dangerous and often illegal means for ending their pregnancies. Many of their children, growing up in overpopulated cities with few opportunities, died before reaching their teens. People with diseases known to end in misery, have been forced to live through that misery without the option of controlling their own dying as they have controlled their own lives. Who, you may wonder, should you stand with? Those who have trusted you, and believed in your vaunted claims to infallibility? Or those who keep pointing out that no one can be infallible, that all of us are finite, no matter what may have been claimed on our behalf by tradition or councils composed of fallible men.
It’s a difficult decision. Indeed, there is all the pomp and circumstance that surrounds such a claim, all the power and routine acts of frenzied busyness that go to defend and buttress that claim against its detractors, all the lobbying that has been done, all the political leaders that have been threatened and suborned, all the organisations that have not only accepted the claim, but have defended it by fair means or foul. If you decide that, after all, the claim itself is and must be invalid, because no one is preserved from all error, and you can see for yourself what has happened as a result of making such an inflated claim, the organisation that you lead will be left rudderless, maybe even a laughingstock to be ridiculed and scorned, and, as a result, an organisation that was believed to be founded in truth and preserved in truth for millennia will founder and shatter into a thousand warring sects and claimants to your supposed importance and infallibility. Dare you act in such a way as to precipitate such an outcome?
The answer, so far, is no. Whether or not you think that the man who placed you in this fix – the man who claimed, and got people to agree, that anyone holding your office must be infallible — was in error or mentally unbalanced, the damage has been done, and you simply have to accept that you are stuck with the claims that have been made, and everything you do must be aimed at continuing to uphold the claim. But you must do much more than that. You cannot just simply claim that this man was right. You have to deepen and strengthen the claim, and commit yourself to it with more insistence than the author of your predicament, who established the claim at a time when the consequences of making it were unclear to many, perhaps even to the man who sought it. At the time it seemed limited to certain exceptional and strictly circumscribed occasions, but eventually it became obvious that it could not be restricted in that way, that the claim to infallibility, ascribed to exceptional cases, would simply bleed into everything that was said by you, your predecessors, and your successors.
The “indefectibility” that was once ascribed to your organisation, that meant that, in the end, the truth would prevail, no matter into what errors the organisation might in the course of history be led, came to be ascribed to a succession of individuals in such a way that a single error in judgement could never be corrected, without it becoming clear that “indefectibility” cannot be ascribed to individuals, because it is precisely individuals who err, and saying of an individual that, in the end, the truth will prevail, is a very different proposition than the claim that, in the end, the organisation will be preserved from error. Individuals err all the time, and sometimes they correct their mistakes, but if someone who is infallible errs, then he is not infallible after all, no matter how many times you say that he has corrected an error in judgement, or that he is sorry. The indefectibility of the church — and of course that is what we are talking about — permits individuals the latitude and freedom of thought to say that, on this or that occasion, the church was wrong; but the infallibility of the pope does not permit for this kind of latitude of thought or expression, because the pope is infallible at the time you are ascribing error to him. And the pope must uphold in the present the infallibility of popes in the past, otherwise his own infallibility is immediately called into question.
This means — changing the “you” of the above discussion to the pope and the church — that the church cannot allow the pope to be questioned, and that any statement that calls the truth of the church’s teaching into question is immediately seen to be anti-Catholic, because the Catholic Church is defined simply in terms of the infallibility of its leader and the Magisterium (the teaching authority) over which he presides. Therefore it is necessary for the church to oppose any claims that run contrary to those teachings, and to use all the power at its command in order to do so. That is probably why, in an article on the London Summit on Family Planning (sponsored jointly by the UK government and the Bill and Melinda Gates Foundation), the Guardian Social Affairs editor, Tracy McVeigh, in her article “Melinda Gates hits out at ‘war on women’ on eve of summit“, mentions the Catholic Church only in the context of saying that Melinda Gates is a practicing Catholic. Other than that she speaks only in general terms about Melinda Gates being
targeted by religious groups, which have described her mission as a “blatant attack on morality” and an elitist effort at population control. [my italics]
Certainly, there may be religious groups other than the Catholic Church or Catholic organisations that are targeting Melinda Gates, but at the forefront of these religious groups the Catholic Church must be, as it has been for many years when it came to issues of birth control, abortion, and women’s reproductive health, somewhere leading the pack.
This is evident from a report in the (so-called) Canadian Free Press on the London Family Planning Summit, which quotes from none other than Wendy Wright (interim director of C-fam — and the annoying opponent of Richard Dawkins in the video clip in my recent post on evolution), to this effect:
This is a new chapter in the population control movement. Elite billionaires and powerful governments use the guise of ‘helping poor women’ to extract permanent funding for abortion-promoting and population control groups. Contraception will have a higher priority than education, basic health care, infrastructure, and economic improvements – diverting funding from measures that empower women and communities. None of the contraception programs help pregnant women or newborns.
Notice the unsupported claim that contraception will be given a higher priority than education, basic health care, and other important things. This is simply thrown in opportunistically, to raise the emotional temperature for the Catholic opposition to any form of family planning. For, while it is nowhere spelt out in the article, C-fam is the acronym of a Catholic organisation (which has duplicates with different names in many countries) the Catholic Family and Human Rights Institute (this link will take you to C-fam’s propaganda against the London Summit).
What Wendy Wright neglects to point out is the number of women who die every year as a result of complications due to pregnancy, especially pregnancy at very early ages. According to the World Health Organisation’s Global Health Observatory:
Every day in 2010, about 800 women died due to complications of pregnancy and child birth, including severe bleeding after childbirth, infections, hypertensive disorders, and unsafe abortions. Out of the 800, 440 deaths occurred in sub-Saharan Africa and 230 in Southern Asia, compared to five in high-income countries.
C-fam’s motto is Defending Sovereignty and Human Dignity at International Insitutions, but not only is human dignity defined in terms of the Catholic Church’s ban on birth control, it makes every effort to frame issues in terms of its own predilections. For instance, its pdf “4 Problems with the London Family Planning Summit Goals” (linked above), states bluntly that “Current family planning funding in the developing world is $4 billion,” and links the reader to a Intrahealth document on global family planning initiatives. This document does include the figure of $4 billion for family planning, but it also includes the following statement:
The current level of contraceptive care in the developing world costs about $4 billion annually but saves $5.6 billion in maternal and newborn health service costs.
And despite all this expenditure, remember, 800 women a day die from complications due to pregnancy. As Stephen Mumford says in his book, The Life and Death of NSSM 200:
It is institutional survival that governs the behavior of he Catholic hierarchy in all matters. The claim that “morality” governs its behavior in the matters of family planning and abortion is fraudulent. The hierarchy has a long history of determining which position is in the best interest of the Papacy … and then framing that position as the moral position. Father Arthur McCormack was for 23 years the Vatican consultant to the UN on development and population, leaving that post in 1979. In 1982 he went public with his conclusion that the Vatican position on family planning and population control is immoral. 
But it is the framing of the issue, and the language that is used in doing so, that is of the greatest interest to the Catholic Church in its many bishops conferences and agencies that take the lead in opposing everything that opposes what has been “infallibly” defined as immoral, contrary to human dignity, and other permutations on positive descriptors of what they stand for.
This is important, and it is clear that this was understood from the start of the Church’s campaign against birth control, abortion and euthanasia. According to a 1971 article — recall that Pope Montini’s (Paul VI) encyclical Humanae Vitae (Of Human Life) was issued in 1968 — by Jesuit priest, Virgil Blum (Virgil C. Blum, “Public Policy Making: Why the Churches Strike Out,” America, 6 March 1971, pp. 224-28), founder and first president of the Catholic League for Religious and Civil Rights (now led by Bill Donahue),
[c]rucial to influencing public opinion is getting the people to define the issue in your way. Since language not only defines the situation but also shapes attitudes, a group’s cause has an almost insurmountable handicap if it permits opposing forces to define the terms of the discussion. [quoted in Mumford, 157]
That is why the Catholic Church continues to use words like ‘kill’, ‘murder’, ‘infanticide’, with all their negative connotations intact, when describing acts that could as easily be called acts of mercy and compassion. That is why Pope Wojtyła (JP II) spoke with such passion in his encyclical Evangelium Vitae of the modern “culture of death,” when speaking of everything from birth control to euthanasia. That is why Melinda Gates, in the Guardian report on the upcoming London Summit on family planning is said to have been opposed by “religious groups,” and uses the word ‘catholic’ only when identifying Ms. Gates as a “practicing Catholic,” because, as Blum concluded, “if the Catholic leadership is to succeed, it must make their efforts look non-Catholic.” (in Mumford’s words, 159) That’s why Bill Donahue and his Catholic League for Religious and Civil Rights continues to attack anyone who dares to criticise the Catholic Church, and why, when Pope Wojtyła’s encyclical Evangelium Vitae appeared in 1995, the American press was silent, even though criticism in Italy was widespread.
Why does the Catholic Church oppose family planning? Because to do anything else would be to expose the lie at the heart of Catholicism, that one person, and one person only at a time, is protected from all error on matters of faith and morals — a sure recipe for mounting error upon error until the structure of the papacy and the church comes tumbling down. But, like the present Archbishop of Canterbury, who seemed to say, against all his best instincts, that the Anglican Communion would not come unstuck while he sat on the throne of St. Augustine (of Canterbury), any papal resident of the Vatican cannot allow that one of his predecessors made a mistake, though the heavens should fall. Such is the power of religious dogmatism.