Every culture has independently developed some type of supra natural being to worship. So there is that. Anyone that has spent much time in the wilderness can understand why. Here, plugged into a city, it is easy to scoff at the barbarians. But even the most cynical city boy will start praying like an altar boy downrange of the bad guys. Belief and truth just depend on where you're standing.
I once heard that described as a "God-shaped hole" in our hearts. Everybody has one. Only God can fill it. And if you don't want God in there, you hang out in discussion groups trying to convince yourself that there is no God. Why else would an unbeliever care so much about arguing over whether He exists?
I certainly would not care about what they believe, except, rats, Jesus expects me to care.