Always stokes my ire a bit when I hear the term 'do gooders' used in anger, probably because I'm one of them. I think there is quite a lot wrong with some of what is being expressed here however.
I think Gary Moll is right that we do need parents to take more responsibility for the 'moral' education of their children, but also that most peoples experience isn't as negative as a few of those expressed above.
Often I hear people talking about their fear of young people, about no go areas, and about how there isn't any discipline any more. Here's news - people have had these opinions of young people since civilisation began to exist. And more often than not it is just fear. The vast majority of young people in Britain wouldn't dream of committing an act of violence against an unknown adult.
Maybe there should be some kind of big stick to hit parents with if their children's behaviour seriously affect the lives of other (and not just if they're perceived to), though in practice I can see this being very difficult to police. But at the same time we need better carrots too - better parenting support and education, more suitable activities for young people to take part in and more information and support in making good life choices. Countries that do these things see lower rates of crime amongst their young people.
And as for the sterilisation comment - I think that's foul personally.