Yeah, part of it is parents bullying the teachers for punishing the bullies. Part of it, at least here in the states, is the constant mistreatment and demonizing of teachers by political figureheads just to gain points from whatever followers they have, and a part of it is way too many kids in one class for one teacher to handle.

That is, in my opinion, the biggest problem. Too many kids in one class and too few teachers hired to teach the classes. And because so many GOOD teachers are mistreated, and education as a whole is under wholesale attack, instances of bullying goes up because most kids know, 9 times out of 10, absolutely nothing will happen to them as long as their victim(s) aren't TOO badly, physically, injured.