This is the title of the last chapter of Alister McGrath’s book, The Dawkins Delusion. It is an important chapter, because it shows clearly why, in earlier chapters, though indeed it was necessary for him to do so in order to make his points with any show of reason, McGrath did not address the question of other religions. The fact that there have been many religions — so many, in fact, that it will doubtless never be known how many gods human beings have worshipped, and why they have worshipped them – is a telling criticism of religion as such, since it raises the pressing question: Even if there were such a being or beings as God (with a capital ‘G’) or gods, on what basis may it be claimed that the god or gods you worship (for any you) are the right ones?
For example, McGrath takes fairly violent exception to the fact that Dawkins describes the god of the Old Testament — the god of the Jewish scriptures — in these words:
The God of the Old Testament is arguably the most unpleasant character in all fiction: jealous and proud of it; a petty, unjust, unforgiving control-freak; a vindictive, bloodthirsty ethnic cleanser; a misgyinistic, homophobic, infanticidal, genocidal, filicidal, pestilential, megalomaniacal, sadomasochistic, capriciously malevolent bully. [TGD, 31]
The only charge on this charge sheet that may be questionable is that the Old Testament God is sadomasochistic. Sadistic, perhaps, but there is no clear sign that this god likes pain and suffering himself, except insofar as he created the world and humankind, and must have known, when he did so, that his creation would bring him sorrow. Otherwise, every other charge can, I think, be met by evidence from the text itself.
As I say, McGrath takes violent exception to this characterisation of the Old Testament god, because — in his view – it reflects a very selective use of the text and “a generally superficial engagement with its core themes and ideas.” (89) Here’s how McGrath deals with the nasty side of the Hebrew Bible:
Of course, many modern Jewish and non-Jewish readers find many parts of the Hebrew Scriptures puzzling, perhaps appalling, through their cultural distance from a long-past era. Historically, it is important to appreciate that these ancient texts arose within a people who were fighting to maintain their group and national identity in the face of onslaughts from all sides, who were make sense of their human situation in relation to a God about his nature their thinking became more and more developed in the millennium over which the material that makes up these Scriptures was being produced, orally and in writing. (89-90)
In other words, if we would only put ourselves in the shoes of those whose experience is reflected in these writings, all would make sense, from the genocidal belief that God drowned all creatures on earth in a great flood, to the ethnic cleansing of Palestine, where, on some occasions, the Israelites were commanded by God to kill all the inhabitants, men, women and children, and did not exempt domestic animals from the general carnage, all life being “consecrated” to the Lord by death.
Besides, McGrath tells us, we must remember the later insights of the great prophets, who directed internal criticism onto their own religion and its practices, condemning acts which were a declension from justice and mercy. Dawkins, he says, “ignores the prophets and the wisdom literature, in which the heights of Jewish moral insight are expressed.” (90) But he ignores something even more important than this. He forgets, McGrath tells us, or seems unaware of, “the Christian insistence that there indeed exists [an "external criterion for dealing with the interpretation of these texts"] — the life and teaching of Jesus of Nazareth.” (90) “The Hebrew Scriptures,” he says, further, ”are read and interpreted through a Christological filter or prism.” (91)
Whew! That was close, wasn’t it? But, sad but true, the Jews don’t have the option. They have to read their scriptures without this filter, and, without it, we are to understand, the violence and evil of the religion unfortunately stands there naked, its evils undredeemed — save of course for the later prophets, who criticised the heart of the religion of Israel, internally self-correcting, no doubt, but still unable to rehabilitate the religion fully. That could only be done through God’s intervention in Christ.
It is important, in this connexion, to consider what McGrath says about Dawkins’ belief that God is a delusion. According to Dawkins, says McGrath:
God is a delusion — a ”psychotic delinquent” invented by a mad, deluded people. That’s the take-home message of The God Delusion. 
Now, while Dawkins does indeed hold that religious beliefs are delusions, he goes to some trouble on page 5 to say exactly what he means by using this word:
The dictionary supplied with Microsoft Word defines a delusion as ‘a persistent false belief held in the face of strong contradictory evidence, especially as a symptom of psychiatric disorder’. The first part captures religious faith perfectly. [TGD, 5, my italics]
Dawkins never says that the Jews are a mad, deluded people. At the same time, however it is important to note that McGrath himself holds that the people of Israel, whose holy book the Christian Old Testament really is, were in fact unable to read their scripture with its full meaning. In order to be able to see what it really means, a Christian filter is necessary, and only this, it seems, can overcome the horrors that are depicted there. The prophets, who at least shone a faint critical light onto some of the most violent and xenophobic aspects of the Jewish scriptures, are not sufficient to overcome the weight of evil with which so much of it is encumbered — though, of course, those evils can be explained (McGrath thinks) by the fact that Israel was struggling to maintain its group and national identity. It can be explained, that is, by tribalism, but in order to see the truth about this tribal god, it is necessary to be a Christian. Supersessionism dies hard.
The fact that there is no evidence for the exodus from Egypt or the conquest of the Promised Land – and very little evidence, if any, for the great kingdom of David or the almost imperial sway of Solomon – and that the stories of conquest and genocide are probably largely mythical — and all the worse for that, since they thus create narratives of monstrous evils in order to emphasise group identity and to encourage group loyalty — should lead us to question the idea, that McGrath so carelessly takes for granted, that these writings record a developmental process (taking place over centuries) of coming to know God more intimately and with greater fidelity.
That’s the problem with scriptures. It is impossible to miss the fact that they are purely human creations, and yet those creations are then trancendentalised and made absolute in a way that other human writings are not, thus fixing a moral base line which, however much later ages may depart from it, and count themselves faithful, will always have a gravitational pull which makes genuine moral learning and progress difficult, and often impossible.
McGrath says that this process of transcendentalising or absolutising “social demarcators” is inevitable. “If religion were to cease to exist,” he writes, “other social demarcators would emerge as decisive, some of which would become transcendentalized in due course.” (83) But why should we believe this? Why could we not pull ourselves free from the miasma of religion, and substitute processes of moral reasoning in its place? The German-American theologian Paul Tillich held that idolatry is precisely the process of transcendentalising and absolutising the human and the contingent. He tried, at the same time, to provide an insight into the pure transcendence of Christ, though this must be adjudged a failure. We are finite, contingent beings. There is no reason to think that we can in fact attain to something which is not tinged with contingency, and the belief that we have attained this — we call such beliefs religious — has been a continuing and, one might think, avoidable tragedy of the human race.
Does this mean that religion is evil? Yes, it does. In the effort to find a fixed point in a constantly changing and contingent world, as religion inevitably does, what human beings have done is to pretend to have access to something that does indeed transcend the human, something that is not simply a human creation, something absolute that can settle all our disputes, complete all our partiality, and heal all our wounds. There is no such fixed point in our firmament, and the belief that there is, despite thousands of years of failure, means that we discount and devalue the human ability to come to know what is best for human life — for our lives – and to put that knowledge into practice.
Religion constantly tugs us back to human solutions of the past, so that, despite what we have reason to believe that we know, we must continually pay our dues to long dead human beings who we imagine were somehow closer to the source of things. Why else should we take what they wrote and try to shape our lives by their values and prejudices? But this belief poisons the very well-springs of human life, which lie, not in past solutions to problems long ago, but in the human ability to know and to understand the world around them. And that we know better than our forbears, no matter how illustrious, is clear from the success of scientific ways of knowing. This does not mean that all knowing is scientific, but it does mean that seeking answers to present problems in the present is more likely to be reliable than putting our trust in the opinions and beliefs of those who lived and died so long ago. As Paul Bloom says, in Descartes’ Baby:
… moral progress is difficult as well because of the connection of morals with religious beliefs. A lot of what we see as right and wrong is based on the authority of sacred texts and beliefs about the wishes of spirits and deities. These beliefs are insulated from empirical evidence and can twist morality in unpleasant ways. 
That is, the “merely” human is so gravely devalued by religion, that we are deemed unable to resolve moral issues on our own without resorting to texts supposedly guided by something beyond the human.
McGrath seems to think that religion is not an evil because religious people do good things. But of course they do! They are, after all, human beings, and if they did no good at all, that would indeed be a surprise. Evolution, as psychobiology increasingly shows, has built moral responses into our very nature. Children as young as three years old, as Paul Bloom has shown, seem to have an innate sense of justice and fairness:
A typical three-year-old can feel embarrassment, guilt, and shame, can become angry when treated unfairly, and, most important, can sympathize with others in pain and act to make their pain go away. [99-100]
So, of course Christians and Muslims, Jews and Zoroastrians, Bahais and Hindus do good. Why should they not? The question is whether they do good because they are religious, or whether they do good because they are human?
What makes religions evil is not only that religions are sometimes the basis for doing evil things. It is because religion places goodness beyond the human. But religions themselves put this claim into question. For there is a strain of violence running through most religions. As Jack Nelson-Palmeyer points out in his book Is Religion Killing Us?, the violence-of-God traditions in Christianity, Judaism and Islam will continue to wreak havoc until they are recognised and rejected (134). What if, he asks:
What if Jews, Christians, and Muslims were to view the Bible and Quran as products of human beings who offered their views on how history intersects with the divine? 
Indeed, what if? The problem with this suggestion is that it would still privilege just these writings as providing access to goodness that human beings are incapable of on their own. But if these writings themselves must be subject to review by human beings if they are not to continue to do harm, then, like everything else that is human, they are as fallible as any other things that are written by human beings.
There are surely many other writings that have an equal claim on our moral attention. On what reasonable basis can the Tanach, the Bible or the Qu’ran — three entirely different human creations transcendentalised and absolutised — be singled out as uniquely authoritative? Indeed, some writings, such as the Greek and Roman, and the Chinese, philosophical traditions, in which the divine plays very little part, are, if anything, much more peaceable and concerned with justice and mercy than any of the world’s great religious scriptures. And why, it needs to be asked, should violence play so prominent a part where history and the (supposed?) divine intersect, that the record of it is so salient in the world’s greatest scriptural traditions? Could it be that absolutising anything human — that is, placing it beyond review and revision – is intrinsically dangerous, and, indeed, evil?