So is the reason for why the main character transferred supposed to be some criticism of Japanese culture or could they not think of a better way to set things up? Because it seems insane that you're transferred because you basically stopped a rape and thus everyone treats you like you're the biggest piece of shit
The fact he stopped a rape is covered up by the influence of the man, as far as the courts were concerned the protagonist was convicted of an unprovoked assault. He transfers because apparently only that high school would take him.
Still silly and there for setup, but that cover up and the fact he doesn't deserve to have his record is a big part of the theming.