Because the thought of an all knowing all seeing all powerful being who created everything and just sits above us all and does nothing with his great power is absolutely the most ridiculous thing that I have ever/will ever hear in my entire life. I live in a place called reality, and I welcome everyone else to come and join me.
I have never believed ever since I was a child, and there is absolutely no chance that I will ever change.
I'll add that the actions of religious people that I've had experiences with have only created my hatred toward all religion.