There’s still the problem of Jedi being taken in as babies. Because of that, their lives as Jedi are all they know. They have the option to leave the Order if they wish, but with a few exceptions, none of the Jedi have lives or key social connections outside of the Order. I’m not counting casual friends like Dexter Jettster. I mean connections that could take the place of a family or a community. It wouldn’t surprise me at all if padawans would stay in the Order simply out of fear of being on their own in the outside world.
This sort of ascetic lifestyle is something that a person really needs to consent to be a part of. I know the rationale, that if you wait too long before you start training, they’ll develop attachments to their family. But that doesn’t stop people in the real world from becoming monks on their own. And feeling a connection to your family is certainly not a bad thing, anyway.
Again, that’s a very modern point of view. No one consents to who their parents are or where they grow up. You could just as soon argue that anyone’s parents are being cruel to their children by not having them tour around the world and figure out which of the thousands of cultures they want to join. I don’t personally agree with having Jedi raised from birth but that’s just me.
And we don’t really know whether or not Jedi could find friends elsewhere. It seems reasonable that they could. In one of the Jedi Apprentice books, Obi Wan finds a political cause on a planet that he agrees with and he’s ready to leave the Jedi to help out his new friends. Qui Gon has to talk him out of it.