"The notion takes hold, that he's a person they can bully and wound, without guilt."
This is a really underfocused aspect of malice in these situations. Everyone is blaming the teachers (rightfully), but it cannot be understated how shitty these kids (yes, idgaf even if they're just elementary kids) really are. It takes a special kind of malice and by extent, evil, to want to harm another one of your peers like this.
I truly believe bullying is a lot worse and more evil and more deserving of a greater stigma/reputational cost than society currently believes. If students have decided that they can enrich or uplift themselves at the expense of someone else's pain and suffering, then I think they've turned themselves over to evil and as such, shouldn't be surprised when the malice they dish out into this world come back to bite them, whatever the consequences might be.
I don't remember a single time when I felt like I should bully someone throughout my entire childhood and adulthood; the notion is unthinkable to me and I think it requires an intentional desire to see someone else suffer for no reason, which to me isn't all that different from plain evil. I really hope all the bullies pay for their sins through experience the same kind of pain their victims feel, which I believe is true justice. Eye for an eye, on some hammurabi's code shit.
Also, I think it was that other teacher who actually stole Misaki-sensei's property. I can think of another reason why she'd try to snatch/push away that documentation Yukito made as proof of his account of events. Feels to me like she stole her own colleague's item, out of jealous for how much she was adored by her own students, then tried to push the blame all onto Yukito, thus why it's inconvenient for her to see Yukito not taking this false accusation lying down.