These are old order Mennonites. These kids likely grew up without electricity, or at least limited use of electricity, they may not have had cars computers or anything like that. This community has likely been self-governing for years, and there are for sure more stories just like this that were swept under the rug. The biggest warning sign to me however is that this sect of old order Mennonites is apparently not very well funded. Mennonite organizations are rich as fuck, and so are 90% of old order Mennonites. The fact that they are not funded well means that even their own church doesn't want them, which means they don't condone the practices of what is essentially a Mennonite cult. Unfortunately this means that they are likely without very much supervision which allows cruel practices like this to flourish.

I say this is a person from very Mennonite family, I even have distant old order Mennonite relatives (albeit ones that act nothing like this).