I'd say that it isn't necessarily the idea of a magic man in the sky itself that makes people do this crazy bullshit, but that these people are already easily influenced and base their entire moral compass around how someone says a supposed magic man judges them.

The idea of a creator isn't conflicting with reality, as we cannot describe what happened at creation (before doesn't make sense since time is also a part of the universe). The idea of an interfering and detectable creator however is at odds with reality.

There are and have been tons and tons of people around the world who believe in said creator without letting it control so much of their lives that they can't even think for themselves.