Dawkins on Morality

I've just finished reading the chapter in Dawkins' book that discusses where morality comes from, whether one needs to believe in God in order to be moral, and whether people who believe in God really are more moral than people who don't. It seems to me that he misses the point. I mean, sure, those are interesting questions to discuss, but the question lurking in the background which he does not address and which subsequently damages his argument is: what is morality, anyway? His claim is that morality is a by-product of evolution, for reasons that he spells out but I won't repeat here. He also claims that we evolved a sense of morality without the interference of God, whom he claims (probably) doesn't exist. Ok. In the same breath he attaches a huge amount of value to morality, to being good to others. That's fine, but this underscores the fact that he's not actually answering the question. If his story is right, then the reason he attaches value to morality must be because we evolved in such a way that we place value on morality. But if that's true, then where does God fit into the picture? He might say this is exactly his point. But I think that the Christian argument goes more like this. Suppose: I'm moral because I evolved that way; I would still be moral even without God; religious people might actually be less moral than atheists, because they are moral out of fear of retribution or hope of reward, whereas atheists are moral out of the goodness of their hearts. But this implies a value judgment that being moral is good; but where does that value judgment come from? From evolution. So if we had evolved to value rape, we would call Christians immoral if they didn't go around raping. But if morality is a by-product of evolution and we know that now, and we have the power to alter the course of our evolution, then if a group of people wanted to value rape, they could call it the next phase of their evolution. After all, more rapes would result in more pregnancies which would result in more replication of the rapists DNA, and DNA replication is the whole point of evolution (more or less Dawkins' own words). So what's wrong with it (if there isn't a God)? It is simply begging the question to respond that it's wrong because it's evil, or because moral philosophers have set down a principle that one should not hurt another human being. But this seems to be Dawkins' answer to the Christians who claim that without God there can be no morality. He's addressing a completely different question from what the Christians are asking, but doesn't realize it. (The question he's addressing is whether Christians are more moral than atheists.)