I'd say atheism correlates strongly with various value judgements. For example, almost everyone who doesn't believe in a god, also doesn't approve of that god's morality. Few people believe that a given god has excellent morals but does not exist. And many people lose their religion when they get upset at their god/gods. Part of this is likely to be because said god is used as the source or justification for a morality, so that rejecting one will result in rejecting the other. I believe there was also research indicating that whatever a person believes, they're likely to believe their god believes the same.