I think that atheists and agnostics belong to the same "church." Neither places any faith in the existence of a deity. And only a fool would deny the existence of "God" if there was irrefutable, uncontestable and absolute (rather than interpretive) evidence of "His" existence. Therefore, if there existed such incontrovertible evidence, then I think that everyone would fall into line. Until such time, there are just varying degrees of belief and disbelief. Presently, I think of myself as an atheist. Before that, I considered myself to be an agnostic. Before that I was a believer in God. My life has been no different as either an atheist or an agnostic. In fact, for all intents and purposes, they are effectively the same. I am guessing that there are atheists who present themselves as agnostics because it may be more politically correct. But really, what is the difference? Neither accepts a deity. You either do or you do not.