I have to tell you, I don't really find myself surrounded by 'badly behaved' adults. Probably because I choose not to spend time with them. I don't know any burglars, or people who have been to prison for violent crime.
If my collegues and friends were badly behaved as children, they've managed to grow out of it. If they hadn't, I suspect our paths might not have crossed anyway.
I know plenty of slightly unpleasant people through my work, but I can walk away from them at the end of each day, and I wouldn't choose to make them my friends.
Similarly my children can recognise and choose not to spend time with unpleasant children or adults. It is not something school has taught them, but normal, everyday interaction with the people they meet. Family, friends teachers, neighbours, children in the park. Unpleasant people are everywhere, you do not have to tolerate their behaviour, that is something I want my children to understand.
And possibly on the other side of the coin, there are parents who pay through the nose to send their children to tiny private schools, where any 'difficult' children are simply sent away. They spent their days with highly motivated children who know what they need to do to coform. They have about as much chance of becoming 'streetwise' as I have of walking naked through Morrisons this evening.
Mollycoddling is not the preserve of HE parents.