Atheist Hussy's latest post is about why religion matters and should matter to atheists. I agree with her that Christianity, and religion generally, has been a disaster for humankind. Religion matters because it is a plague upon human beings. Intellectually and spiritually it is the equivalent of tuberculosis or the Black Death for emotional and intellectual health.
However deserving of our hatred and disgust religion may be, the fact remains that religion was (and remains still) important to the social, intellectual, and emotional life of the vast majority of human beings throughout all of human history. Complaining about religion bears an uncanny resemblance to complaining about a close blood relative who is simply a manipulative prick. The suspicion that you related by more than blood is unshakable and unprovable.
I haven't worked out all the details but it seems very likely that the criticism that religion is a curse because it is false, irrational, immoral, harmful, etc. is grounded in morality. "Grounded in morality" means that not all beliefs, actions, thoughts, intentions, behaviors, etc. have the same worth. And further that this difference in worth is not to be found in the natural world.
Lurking further back, intuitively speaking, is a faith in the rationality of the natural world. This faith is simple enough: the natural world is amenable to complete description and understanding through unaided human reason. Generally speaking, the order and arrangements of thoughts in the human mind can sometimes reflect the order and arrangements of things in the world.
Once God is banished from explanations, a question arises: how and why does the order and arrangement of events and objects in the phenomenal world (sometimes) correlate with the arrangement and order of the cognitive processes of the human brain? With God, of course, it's easy: God made the world. God made human beings like him. Humans can know the world because humans partake of Divinity: humans are made in His Image. I don't have a solution to that problem.
That is one conundrum that I wanted to point out. Another conundrum and more relevant to Atheist Hussy's post is that the sheer irrationality of religion calls into question the necessity, wisdom, and rationality of elevating reason and rationality at the expense of religion. The typical resistance of fundamentalist Christians to reason, empirical evidence, and rationality in general means that those things are not essential to human life.
Fundamentalists are themselves a walking, talking attempt at a refutation of reason and inquiry. Hurling down upon all the curses which reason may invent does not touch upon the taunt to reasonableness that is their life. They live as if to say that reason is shallow, inconsequential, and irrelevant to most of human existence.
The immunity of our fundamentalist Christians to the charms and beauties of reason and rationality strongly suggests that we do not understand our own love of reason and rationality as well as we like to think we do.