This is like the movie "Lord of the Flies" where the kids run wild because there is no adult supervision and structure.  Left to their own devices, kids can become cruel.  The bullies quickly learn that there are no consequences for their behavior.  The lack of discipline is coming from the school administration who, apparently, believe middle school kids shouldn't be held accountable for anything.  

In the movie, "Lord of the Flies", the good boys raised with compassion and discipline were driven off or killed by the gang ruled by a bully.  

The parents of kids who want to learn need to pull their kids out of this school.