Does it not take as much 'faith' not to believe in god as to believe in it? Atheism is the belief that there is no god. nothing more then that. Science is what 'god' is to most Atheist that is their belief. Sure Atheists don't go to church or anything as of such but they still get together for a joint reason.
Atheism really doesn't fit the definition of 'religion' but it is still close to one in several ways is it not?