Not offered by me, but at TCS Daily. If Hitchens proposes that atheists can claim their morality from the literature of theists, he is not necessarily endorsing the bible. He is endorsing a morality that draws its tenets from the same ethics as the bible, but you can have one without the other. Altruism is the same ethical code of Christ and the communists. Who you end up sacrificing yourself to (God or the State) and how the sacrifice is accomplished (through self-discipline or through force at the hand of the government) varies, but in the end you are the sacrifice.
That atheists claim some portion of a well-accepted ethical code is not refutation of the argument against a belief in god(s). What moral code to follow if you're not following the one laid out in some religious document is a legitimate question. I've found mine and it's not atlruism.