Luckily, we don't.

As long as they were no burden to others, i'd say they can play 1698 as long as they want. But they are limiting their childrens world view, and that's where they become a problem.

It is not just an Amish thing. If an adult wants to participate in a brainwasher cult, it's one thing, but brainwash kids for a cult - nope.