"This assumption about religion being necessary for morality is recognized and used as a justification for religion. When atheists provide arguments showing that religious beliefs are incorrect and illogical, a frequent response is that religion is still good because it's needed for morality. The question of truth is dismissed as less important than the question of usefulness. If morality is a good thing, then atheist arguments fall on deaf ears. And more, the act of willfully ignoring evidence or argument is performed with a sense of moral pride. This position rests on the myth that morality requires religion, and that you have to accept religion despite any flaws or abandon morality. This justification of religion is just one more consequence of the myth."
Morality Needs No God, ch. 1 (2011)