But Dawkins’s theory of the “moral Zeitgeist” clearly does not solve the problem of how to validate moral ideas by reference to reality; it just treats collective opinion as though it were objective fact. That a changing moral consensus exists and that most people unthinkingly absorb their moral views through social osmosis does not mean that the consensus is correct or that people should acquire their moral views this way. Although Dawkins acknowledges that we can and must judge the contents of the Bible by reference to an independent moral standard, he fails to recognize that we can and must judge the social consensus by reference to the same.
This is an excellent article about the "New Atheists". Although they deserve a lot of credit for illuminating why various religions and their dogmas are contradictory and anti-life, they fail to offer a positive alternative to religious ethics, often times invoking faith or some arbitrary reason for their own beliefs.
Full article here. It does an excellent job of showing these atheist's own contradictions and short comings. And offers it's own solutions.