It is what I know. A belief is not backed up by fact.

Simply religious people. There are men who swore they were a god, then men that swore they were the sons of gods, then men that swore they were given their positions by god. Kings, other religious leaders, entire religious sects... and each one of them claims a different thing will lead you to some sort of beautiful afterlife, and that everyone else will burn for eternity for not believing in your god.

I am not saying God doesn't exist. It is simply that there is quite a bit of evidence that seems to support the fact that he doesn't. If he does exist, well, he has a lot of explaining to do.