Religion is about turning untested belief into unshakable truth through the power of institutions and the passage of time.
The enlightenment is under threat. So is reason. So is truth. So is science, especially in the schools of America.
If children understand that beliefs should be substantiated with evidence, as opposed to tradition, authority, revelation or faith, they will automatically work out for themselves that they are atheists.
I suppose if you look back to your early childhood you accept everything people tell you, and that includes a heavy dose of irrationality - you're told about tooth fairies and Father Christmas and things.