I'm late to this party (just finished this series yesterday), but this was the first thing I came here to comment on. I'm hoping there's more of it that I've missed in the last 40 pages of discussion.
When I tell people that the Jedi are the bad guys, this kind of "training" is exactly the kind of stuff I'm talking about. Forcing children to separate from everything and everyone they know isn't how you train an order of leaders, peacekeepers, or anything resembling an emotionally or spiritually balanced adult. That's how you raise child soldiers and cults. Is it any wonder that Kylo Ren rebelled from this type of toxic environment? Sorry Luke, I know you didn't have a lot to work with, but it really was better for you to hide from the galaxy than pass this on to future generations.