That's not exactly true, as a period of adolescent self-discovery and active choice in joining the faith/community are common in Amish communities; it's usually called rumspringa. The point could be made that the rate of exit is extremely low and therefore perhaps the youths are overly programmed, but that's not a given - they are raised in a tight-knit community which is a powerful motivation to stay and not something the majority of modern Westerners actually experience.