I think this oversimplifies it. I didn't grow up Amish, but I grew up in a tiny Anabaptist denomination that had a lot of cultural similarities with the Amish (but technology was allowed).

While it could be true that "those values are very dearly held by those people" you are not counting those who grew up Amish and left (or were expelled) because the values were not dearly held.

Speaking of my own experience growing up Anabaptist, I witnessed misogyny (women were not allowed to teach men) and a forced social cohesion that bordered on cult-like (people had to vow to follow very serious rules, including never to visit any other denomination, and pledge themselves to the denomination, and if they committed a "sin unto death" they were excommunicated from the community with no chance for reconciliation).

I can say with confidence that although there were some aspects of my religious upbringing that I appreciated, overall it was a bad religion that did not bring the best out of people.