Man, even though it's wrong for Shiori to be harassed, but if it's for Suzuki's scum to suffer, I don't care much, it will be truly a joy that his whole "perfect and just" life is falling apart, if you do things bad, wait for consequences, but if you are a fucking scum, expect even worse things, I want you to experience what the MC suffered, know that his beloved daughter is harassed, that his wife leaves him, that the crazy sensei becomes a yandere (which is scary, because he seems to act like that) and tries to kill him, one reaps what he sows, and he has a whole plantation of many seasons to attend to.
I continue in my assumption, the Sensei recorded each act of harassment towards Shiori, so that at the time of filing the complaint, it cannot be denied that there was no such harassment, which is one of the main causes that the harassment does not stop, Just saying that there is bullying does nothing to stop it, and even less in a shitty world, with shitty teachers like there are in this manga.
I believe in Sensei, the manga makes us believe that he is the bad guy, and that this is a way to get his revenge (as in redo healer), but he also has that double standard of helping the daughter of the boy who harassed him .