First of all, what have you got against sex and weapons? Are you a commie or something? (/jk)

Second, yes, it's true that there are gangs, crime, bullying, popularity-obsessed people, etc., in the real world. But the difference is this: outside public school, those are bad behaviors, which lead to unsuccessful outcomes. If you want to teach children to succeed in society, you need to teach the opposite of what public school "socialization" teaches.