Um, hello? HIgh school settings are pretty much de rigeur since the dawn of manga, anime, and Japanese shows in general. "Project A-ko", "School Rumble", "Crows"/"Crows Zero", "Battle Royale" (not exactly school, but schoolkids), "Natsumi Yuujinchou", "To Aru Majutsu no Index"/"To Aru Kagaku no Railgun", etc., etc., etc., are all great examples of titles throughout the media's history that involve schools/schoolchildren in some way.
Complaining about any particular trope - or the media in general - by saying "{x}% is crap" is also quite disingenuous; that's ALWAYS been the case. Go watch "Ba Oh: the Visitor" or "MD Geist", and then try to tell me how great anime was in the past; I can pretty much drown you with similar examples *spits*...
Yes, there certainly are bad series/movies/manga. And? Don't MAKE me slap ya down with some "Marine Boy", beeyotch!