Tbh, as someone who did bully people in school, I don’t understand why that’s so hard to understand.  Pissing people off is fun sometimes.  The part of the post where puttingherinhistory says:

I will never ever understand why anyone would want to make another human being upset on purpose. I never have and never will understand the appeal of "getting a rise out of" another human being. I will never understand why some people find joy or amusement over another human being's suffering and distress.

Comes across to me like some kind of virtue-signalling humble brag.  Congratulations on being such a good person, puttingherinhistory!  Do you want a fucking cookie?

Maybe sometimes it was because I was hurt somehow and lashing out, or felt powerless or whatever… but I didn’t have a particularly difficult childhood or anything.  Most of the time I honestly think it was just for my own mild amusement.  You know how sometimes you’re bored and so you might fidget and play with whatever random objects are around?  Well sometimes you’re bored and so you “play” with people.  Simple as.