[Arawn]

I love this mentality. When a christian does something bad, he's a bad person, but when an atheist (or merely suspected atheist) person does something bad, then atheism is bad.

Atheism is simply the opposite of theism, namely, not believing in God, thats it. It is not an ideology, or a singular easily described philisophical outlet.
It is a generic bannor that can include anything from punk students who can't get enough of nitzsche, to certain schools of buddhism.