That is something very sad, unfortunatly.
Many of those kids (or maybe not so kids) have too much liberty from their parents who know that their son/daughter doesn't have proper behaviour, but still let thembe, probably giving even more liberty. With liberty comes responsability. If they aren't responsible, they should be less free.
I had some classmates that were too free and little or no responsability at all. Those did whatever they wanted (with the other students) and get out of it without any consequence.
I have some other friends that are also free (not as much though) and are quite responsible. They have very good behavious, are very good friends, get well with everyone and, eventually, have (much much) better grades in school than the others.
With this, I don't mean that "free" is sinonym of "irresponsible", but too much freedom (or liberty, whatever you want to call it) frequently lead to irresponsability, bad behavious and bad grades at school.