not that i condone anything extreme but maybe if some of these girls get choked a little they might change their behavior
The problem isn't them changing, they have little by little in different ways.
The main problem is, they never repented to the victims they caused. So far, the only one who has faced any real consequences for their actions was Tsubaki. Not to mention, the school itself hasn't faced any consequences for the things these girls have done. In a realistic setting once the crimes of these girls get out (and yes a good amount of what they have done are in fact crimes), that school will have to compensate not only the student victims but their ex-employees who were victimized by these girls. Erina needs to die though, nothing can fix that broken bitch.
It's the one reason I hate that bitch of a old friend, now principal of Jimi's. If the truth got out about her little sister, her family and her career would be over. The damage done to Jimi, he would be able to go the rest of his life without working. Physical damage, mental damage that resulted to suicide attempt, career damage (which she help put back on track) and reputation damage. That old friendship went out the window when she found out what her sister did and tried to silence Jimi until he twisted it into blackmail. After that flashback....the fact that she actually had the balls to slap him that one time tells me that a loooooot of characters in this manga lack anything resembling accountability.
......that second part had nothing to do with what was said, just rant I've been holding in since I started reading this....