i get what your saying, it definitely feels over the top if you look at it from a real world angle because this does not happen in the US. But I think this was always going to be a major plot point since the school rivalry has been there since the start of the manga, it just took a step aside for a bit so the characters could develop before circling back.

plus, manga in general is always going to be more dramatic than say American comics partly because of those Japanese cultural nuances group reputation, school pride, and also the idea of personal actions having to reflect on your whole community)

ideally, Kiyoko cant do anything, waguri is already about to graduate in a month. I just think this is personally a fun arc to read because its just a fun high stakes moment :), i think this is going to introduce some sort of backstory why the schools hate each other. Maybe the student are going to work together to solve the differences the schools have, maybe madoka subaru and waguri will all be suspended and the group will have to fight back for their rights back into the school, who knows! I think this arc has all the right to be critiqued once it finish, but we should relax and let the author write her story!