Ok I'm copy pasting my response to somebody else in this thread then adding to it

I think it's important to teach children about religion for one big reason:

"Why?"

By being frank about how nobody knows if, what, and to which degree these tales are true and why people may believe them, along with a healthy dose of science and never stifling their questioning, they can maintain that wonderful "Why?" and know to question even science (a fair few people these days will believe any outdated or just plain wrong "facts" because science is attached to it. I remember one prof likening it to, well, a new religion, which is bad as science shoukd always be questioned - it's the only way we figure out what is wrong and how to correct even the most accurate theories to be even more correct)

Plus, if they do follow the religion in the end? They are following it with a questioning mindset. Fear is a horrible idea - It just risks making them into an anti religious zealot