I see atheism as a natural consequence of skepticism / critical thinking which I see as an outcome of a valid, supportable epistemology (affording belief only to the substantiated).

I'm not sure what you mean by "moral imperative"; I feel my personal integrity compels me to be honest with myself and others and to have supportable beliefs. But it's not incumbent on others such that I should try to force them to agree with me. After all, I want theists to not proselytize me or impose the requirements of their ideology on me. I can't very well ask that and not do the same for them.