I see your point here....but I actually think it is because people use the word Atheist loosely when they really mean they are Agnostic. Atheism - the belief that there is no God - is in itself a belief. Agnostics have a problem with beliefs based on faith and no apparent evidence. I suppose to be fair a lot of "Christians" use that term loosely too as they appear to believe in their own version of the Christian God, cherry-picking the bits from the Bible that support their own social views.
RE: The word f..k
Nice p.c today, by the w.y!