First thing first, bystanders are also bad. They saw, but they ignored, feigning ignorance and avoiding themselves so that they won't be involved. Even if they had some sympathy, it wouldn't be enough, a mere sympathy won't save the victim. I know, a certain action we do can make the victim's condition worse, but that doesn't mean that we should just ignore it. Let's imagine we are in the victim's condition, do you really think that you can solve everything yourself while mentally suffered? Mostly not.
So basically what I want to say is that I hate him letting her getting bullied, I really hate seeing this kinda condition. It makes me want to jump into the scene and punch all of them (except the victim of course).
Well, it doesn't justify what she did though. I'll be happy if she avange the bullies instead, pretty hippocratic, aren't I?. But I think it'll make the story less "depressing" in a certain way