But it is questionable if atheism can take us this far. Probably not. Atheism can support utilitarianism, and emotivist ethics, but atheists overreach when they claim theists are morally wrong. The atheist cannot, without warrant, call certain acts "good" or "evil."
This is a metaethical issue. I'm now reading three books that add to metaethical studies. They are...
Atheist Overreach: What Atheism Can't Deliver, by University of Notre Dame sociologist Christian Smith. Smith argues that "the naturalistic cosmos that is the standard operating worldview of atheism cannot with rational warrant justify the received humanistic belief in universal benevolence and human rights." (P. 124)
Science and the Good: The Tragic Quest for the Foundations of Morality, by University of Virginia professors James Davison Hunter and Paul Nedelisky. They write:
"When it began, the quest for a moral science sought to discover the good. The new moral science has abandoned that quest and now, at best, tells us how to get what we want. With this turn, the new moral science, for all its recent fanfare, has produced a world picture that simply cannot bear the weight of the wide-ranging moral burdens of our time." (Kindle Location 112)
This, say Hunter and Nedelisky, is "moral nihilism."
Scientism and Secularism: Learning to Respond to a Dangerous Ideology, by theistic philosopher J. P. Moreland. Moreland writes: "Given scientism, moral knowledge is impossible. And the loss of moral knowledge has meant a shift from a view in which duty and virtue are central to the moral life, to a minimalist ethical perspective." (Kindle Location 422)