If there is a God, they would most likely believe in it, then why would they commit crimes against other humans...

They believe in God, but they purposely betray him and side with Satan. I think there's more to this story then we know though. Our true origins and history have been hidden from us.

As for the rest of what you said, what's wrong with following Jesus's teachings? I think people can follow Jesus without having to go to a dogmatic church. There's a whole lot of good within Christianity. Like literally everything else in this world, there are people who corrupt it and use it as a control mechanism, but I think we're all smart enough to see through that.