The question atheists and nonbelievers should ask of religion is not is religion false (or true) or irrational or a crime against humanity. Rather questions should be posed that seek to understand religion in spite of its obvious irrationality, stupidity, and hatred of individual autonomy.
What is religion good for, even if it is not good for anyone who values the ability to make their own decisions without heavy-handed guidance? What needs to be true about the world in order for religion to be good for human beings? That strikes me as a far more useful inquiry. That the answers are something no religious person would look kindly upon is something else entirely.
What morality does religion most generally inculcate by example? The answer is obedience. This also explains why religions hate reason and fear the use of unfettered reason. Unfettered reason is, of course, reason "unenlightened" by the teachings of the local religion. Hence the absurdity of religious doctrine. Obedience and sacrifice: the more absurd and even bizarre a Christian's belief, the greater the proof of his proficiency in obedience. This is why Christians are so heavy-handed in their interpretations of Scripture.
The lack of good sense, restraint, rationality, and lack of any credible evidence is hardly an objection to a good Christian. In the bizarro world of Christian fundamentalists obedience is all. A Good Christian need only obey the Idea and The Desire for Christianity to be True.
The God of the Christians is not The God of Love, but the God of Obedience. Christians worship obedience.
Oh, and for the oft criticized God of the Old Testament who was full of anger and vengeance? If as a thought experiment, the (ethnic) group to which a person belongs is completely determinative of what a person is morally, religiously, and spiritually, then the Old Testament makes perfect sense. One member of the tribe sins against God, then the whole tribe sins against God. If one human being disobeys God, then all human beings disobey God. Once any concept of individuality that we today might recognize is treated as aberrant and marginal at best, then the Old Testament God and the various seemingly irrational doctrines of Christianity don't appear so irrational or insanely cruel.
To sum up:
Religion = obedience as highest virtue + elevation of group membership over individual identity. With this formula, the absurdities of religion are no longer absurd, just abhorrent.