I don’t know for sure but it must be state laws. I believe Georgia has has laws against it I know California does. It really creates so much needless nonsense and it would require the US congress to fix but the GOP has made that entire branch of government, practically, non-functional.
This has been their MO for years. A good documentary called “Jesus Camp” was made in like 04. It was about a children’s religious summer camp. It ended with a bunch of children praying to a literal life sized cardboard cut out of W Bush. Those kids are like 30 now and likely have their own kids. They’re just so fucking weird.