You know there can be 'ferals' in private schools too right? I'm not sure what people class as 'feral' - but thinking of my local private school, there are certainly families who don't have alot of money, families who don't always wear shoes in public, maybe aren't the cleanest or most politely spoken.
Drug dealers and alcoholics aren't limited to income or socioeconomic standing exclusively either, I know of several very well off business people who smoke plenty of dope and send their children to very exclusive schools.
I understand where you are coming from with the influences on your children and choices made for schooling to try to avoid this, but I do find the implication that private schools are free from such influence quite, well, snotty. That choice is certainly not racist - but I am sure there is some 'ist' to describe it.