I'm not saying that parents shouldn't exert some control -- it'd be irresponsible not to. However, parents should not control all of their kids' interactions, because outside of communes and tyrannies real life doesn't work that way. One has to deal with all kinds of people, and it's not something one picks up easily upon leaving home. Kids have to learn to deal with people early on.
In the end, it's a delicate balance of freedom and protection.
Homeschoolers tend to be quite protective in the first place, and need to be careful about overdoing it. I've known several home-schooled kids who have difficulty interacting with others, and they tend to be the ones whose parents are too protective. (I'm admittedly painting with a broad brush here, but I trust you'll see what I'm trying to get at.)
Public schools, like the army, put a lot of disparate people together in the same place, and they have to learn to live together. That's an important and useful lesson -- provided, obviously, that there is discipline to keep the bad actors either in line or out of the picture. (Lack of serious discipline is one failing of many public schools).
And even if parents are over protective, so what? Children will grow up someday and learn to interact on their own and hopefully not to repeat their parents' mistakes.
All too often they end up as ninnies. There's a reason that "momma's boy" is (or was) considered to be an insult.
The purpose of education is entirely different from the purpose of boot camp.
Education is meant to enable the individual to reach his potential- to become the best person he can be. Boot camp is meant to develop a group men into a cohesive unit.
So, what is it that you're proposing?
All too often they end up as ninnies. There's a reason that "momma's boy" is (or was) considered to be an insult.
Well, I'm sure if somebody tried hard enough one could pretty much level any charge against the way children are brought up. But, that is a matter for the family to deal with, not society.
And what evidence do you have to support this? Other than anecdotal, that is.