As is your right. It doesn't make them stupid, though, nor should they be ridiculed. You believe God does not exist, which is an admission of faith itself. Obviously others disagree for their own reasons. Many intelligent people are religious, so apparently faith in God is not an admission of stupidity.
Some things require faith. Everyone has faith in something or another (not necessarily supernatural, just in general). The matter of God is one of those things, so you will never receive your proof.