What can be made of atheists, then? If the evolutionary view of religion is true, they have to work hard at being atheists, to resist slipping into intrinsic habits of mind that make it easier to believe than not to believe. Atran says he faces an emotional and intellectual struggle to live without God in a nonatheist world... The comforts and consolations of belief are alluring even to him, he says, and probably will become more so as he gets closer to the end of his life. He fights it because he is a scientist and holds the values of rationalism higher than the values of spiritualism.
This is sort of like the argument I've been making, on naturalism mailing lists and elsewhere. Atheism, while more or less true, is too cognitively expensive to really be a foundational philosophy, at least on a mass scale. I think some of the rigidity of hardline atheists is a reflection of this -- they need to be very aggressive in order to maintain their belief against not only the external believers, but against their own repressed tendencies towards belief.