[ethbr1]

I would say that much of adult society still runs on "fitting in" (e.g. social groups, corporate hierarchies), ergo being able to do it deftly is a huge life skill.

There's definitely a stigma around adults engaging in specific types of bullying (physical) and bigotry (e.g. protected classes), but society as a whole rewards more subtle bullying (political power dynamics) and ignores subtle bigotry (e.g. caste, microaggression).

The point of socialization, and indeed bullying itself, in school is in no small party to teach everyone (bully and bullied) what acceptable and unacceptable forms are.

Absent that, you either get people who are worse bullies (because they never learned where the line was) or are fragile (because they never learned where the "I should/shouldn't be able to handle this uncomfortable thing" line is).