When someone says that a lack of religion leads to a lack of morality, what they're necessarily really saying is that they're so deeply sociopathic that they not only can't reason morally, but can't even envision the possibility of doing so. They're effectively stating outright that they can't even imagine arriving at sound moral judgments through the application of reason, empathy and concern for others, and that the only way they can even conceive of morality is as a set of rules laid down and enforced by some enormous daddy figure who's going to punish them if they break them.