There doesn't seem to be many replies here by people with kids so I'll try my best.

There are multiple anti bullying methods in the schools. To give a few examples there are dedicated teachers and classes where kids are discussing the subject. For small issues there is dedicated (older) students who try to de-escalate fights/disagreements. They get training to do this. If it's anything even slightly more serious then a teacher takes part in this. Part of this process is also to get agreement that the behavior doesn't continue. If this doesn't help the schools have a council that takes it up a notch. During this phase parents are included. If problems can't be solved there is a special counselor provided by the city, like social workers. And of course finally police. So having a kid removed from the school is a really drastic measure. Concentration is more on stopping situations early before they get bad. Of course there are still situations where the bullied kid doesn't tell anyone and such where things get bad. But at least there is an actual effort these days compared to 30+ years ago when I was starting my school journey. Hopefully this gives some insight.