Atheism, naturalism, and the way things ought to be

In an occasionally thoughtful but mostly silly attempted takedown of the so-called New Atheists (Dawkins, Dennett, Harris and such), philosopher John Gray writes that

there is an irresolvable contradiction between viewing religion naturalistically — as a human adaptation to living in the world — and condemning it as a tissue of error and illusion.

-John Gray, What Scares the New Atheists

No, there’s not.

There are lots of human adaptations that are useless or outmoded. Racism, sexism, and other forms of bigotry have at least some naturalistic explanation in terms of evolution, but we certainly ought to condemn them despite this history. This is of a piece with what I understand to be Gray’s general opposition to a sort of Whiggish belief in progress and humanism. But Gray’s argument seems to be another, somewhat disguised and inverted, attempt to derive “ought” from “is”: we are certainly the product of biological and cultural evolution but that doesn’t give us any insight into how we should run the society in which we find ourselves (even though our society is the product of that evolution).