Way to both miss the point directed at you, and specifically demonstrate your inability to empathise with the actual problem.
Maybe you should stop replying to someone with a lack of the ability you possess then. Or maybe stop turning the conversation to personal attack.
For the record that kind of indiscriminately bitter lashing out is something that routinely comes up in the retrospections of people who were bullied as children. It's basically just symptomatic behaviour anyone who's serious about wanting to help them has to accept until they recover enough to get over it; rather like how injured animals in pain are wont to bite anyone who comes near.
My problem with her character is that it seems like she is conscious about hurting both Sakura and the teacher, not simply "lashing out" on them because she is hurt. These characters of Kodama's works always have that side of them who are consciously morally at fault too.
You can be bullied and lash out on people who try to help you without actually meaning to hurt them.
You can be bullied, but consciously try to unload your frustrations to anyone you can, both into innocents and the perpetrators. In this case the innocents.
Again, I'm not saying what she does is way out of proportion either, I get it, but I'm also pointing out she isn't completely innocent here either. I'm sure she will eventually get help, but right now she is also being a perpetrator. Depression is not a free pass to hurt others, otherwise everyone in this world would end up recreating the cycle.