Theres just no reason to believe it in the first place. It goes against logic and science and common sense. If somebody tells you to believe in something why wouldn't you question it first? And if it seems like a load of shit to keep ancient societies in line then it probably is.

Of course we don't really know much about the universe and its creation, but thats no reason to believe the first guy that comes up with a story to explain it. I think a lot of people are not smart and they just want a nice comforting story they can believe in because the truth, that we really have no idea what the meaning of life is, terrifies them.