This is the biggest misconception I see amongst atheists. They think they are rejecting one idea, so-called "God", when in fact they are rejecting 4.7 billion different ideas, without having even understood what 4.6 billion+ of them are. They reject the God of their parents, and then extrapolate to all the others, deeming them all "one idea".
Atheism is a hold-out of the old "single reality" idea. Ironically both atheists and strict religious fundamentalists share that property: the belief in one true way to understand reality, whether it's God or not-God. Rather than a willingness to allow others to define reality on their own terms.