You have experienced what seems to be the norm in today's society. It's the all about me mentality. As others stated, we don't do any state parks anymore due to those exact experiences. Nor do we camp on holidays either, it seems it's prime time.
We have approached park owners without any support. Honestly, it seems like way to many young people are wired with a short fuse. That and alcohol is a bad combination. It isn't worth trying to resolve things peacefully anymore. We'll just pack up and leave, usually early the next day.
Since we bought the MH we started camping at more resort style places where lots are purchased ( and rented). Problem solved.