Why should it be defined as a belief? Atheism is about the lack of belief in god. I am an atheist... and I don't have beliefs. Atheism isn't a belief system and doesn't entail anything related to one.Why cannot atheism not be defined as a belief? Atheists believe there is no god, with the same certainty that the devout believe there is a god.
Do you know atheists personally and have you asked them instead of making assumptions?That the atheist does not have a faith would seem to be more accurate. He is not relying on trust in a deity, commonly defined as faith. It probably would not be fair to describe an atheist as "trusting" in his belief in the absence of a god. He simply lives a life that doesn't rely on faith in anything necessarily, although he may have faith in people, governments, philosophies, etc., or he may not.