Bullies and how they work.

 There's literally no grimmer punishment than getting humiliated by your peers when you are young at school.
Notice how adults as mediocre as we are, quickly forget how terribly dreadful it was to fall into the trap of, or become by proxy the butt of someone's joke, a joke that will involve the participation of the whole class or even the whole year.

And how ridiculous the concept of safe is in schools, when the irony is there is nothing safe. It is a place of social danger. Bullying exists at the same level as always, it was just upgraded.

It has become more of a challenge. And also much more rewarding. Instead of leveraging the sensitive prejudices the bully find himself navigating and engineering situations to make his target seem like the tyrant. And as children naive many get sucked into a situation that paints them the bigot.

The bully continues unaffected. And the teacher pretends that level of manipulation does not exist.
The shame and agony of becoming a pariah when your greatest hope was to belong is worse than losing your job as an adult. Possibly worse than a break up.

Because they haven't built the emotional fortitude to deal with being blindsided on such a level.

Never underestimate a bully.