Well people refrain from evil for either reasons of morality or of selfishness.
Which goes to prove that all morality stems from religion (or it isn't actual morality, rather selfishness) that brings us back to the point discussed that atheists can't be moral (or they can't be atheists) how that be brings us back to cursing had yet to be answered.
Let me clarify. I didn't mean communal organization as in an actual group of people enforcing it. I meant community structure that was formed as people came to sense what needed to be done - or not done - to create a livable world. Ideas such as possession, value of life, not paining others, actually helping others, and more. Once they were established as beneficial and leading to a more stable living environment, they get passed down for eons and it becomes innately right or wrong within those communities.
Most people would agree that they feel stealing is innately wrong. Or murder. Or rape. It's only people that feel the need to incorporate religion into morality for some reason that disagree.
Or if it makes you happier, drop the word morality and refer to it as innate wrongness/rightness.