Early on in my time as an atheist, I went through a "religion is stupid, therefore religious people must be stupid" phase myself. But then it occurred to me that I have about as much concrete proof of God's non-existence as believers have concrete proof of God's existence. Atheists and believers are making an equal leap of faith when they say "There is a (or is no) God".
This is why atheists who bash religion piss me off. They're being just as dogmatic as the assholes who bash atheism.