That bullying has beneficial side effects too.
Yes it can be awful for the recipients but really, the time you spend in school is so short in the grand scheme of things.
Like they said, it can act as a social watchdog that can course correct weird behaviour, and the lack of bullying probably contributed to the explosion of LGBT shit, the mainstream acceptance of "nerd consuuuumer culture" etc... Basically anything that's ruining the west right now.
Because now it's cool to be "different" when it very much used to be the other way around.
And that was a good thing, it led to higher societal cohesion.
Just take this site, the very concept was built on laughing at people that show abhorrent and unusual behaviour.
Because that's something that's deeply ingrained in us humans, it's almost tribalistic. We shun the "other" because our brain tells us that it feels right.
And without that built-in reflex we, as a species, would not have gotten as far as we did.
And the suppression of that might be part of the reason why we're on a decline right now.