How to define "Religion" as a whole?

Well I was saying that it really doesn't fit even if you restricted to that particular definition... unless you look at it as the rejection of another person's perception of truth to be a perception of truth (E.G. if person A is wrong therefore person B is right) but even with that thinking it still doesn't match up, in that atheism has nothing to do with an explanation on how the world works, granted there are shared views among most open atheist, but those ideas are not dogmatic or exclusive to atheism (e.g. you don't have to accept evolution to be an atheist).

You could say the same about people who are catholic, not everyone follows the same principles. People practice their religion in different ways, with Atheism there is no institution that dictates what's in and what's out so we may have very different views inside the same religion.