Everyone is gullible to some degree - it's necessary for imagination.
It's necessary for survival. Children instinctively believe anything an adult tells them, which is helpful when they're told why they shouldn't play in traffic, but less helpful when they're told that they were created by an invisible genocidal psychopath who will torture them without end if they don't do exactly what He wants, and that He wants them not to question anything. Of course, gullibility declines with age, so once such an idea is implanted in a child's brain, it's almost impossible to remove in adulthood.
If the "invisible genocidal psychopath" that created them is going to "torture them without end if they don't do exactly what He wants, and that He wants them not to question anything," then it is extremely good that the children are firmly warned.
But since God created people, and since God is not like that "invisible genocidal psychopath," it's good to teach the children about God while they are still gullible.