Abuse often comes with a rationale for how it's actually a defense. Many of the abusers even believe it, having a twisted psychology that depends on reflecting any and all insecurities onto the people who reminded them of them, regardless of whether it was justified. Tell someone with this mindset that something they said was racist and they'll find a way to understand this as you being rude to them, bullying them, and maybe you're doing it because you don't like, say, white people (etc).

This functions well as propaganda for the normalization of oppression as well, as the reflection at the heart of those abusers is in all of us, we just aren't as wedded to it all the time. It pops up again and again in propaganda used to support ethnic cleansing. Zionists use it, of course, but so do Azerbaijanis targeting Armenians, so did Boers targeting basically anyone not lily white, so did Nazis. Extreme oppression is justified as a defense of the oppressor.

Dehumanization assists with translating the most extreme belligerence imaginable as merely self-defense. An elevation of "yours" far above the target is valuable, as you can feel comparing, for example, feeling slightly uncomfortable in a Taxi because not every person around you supports the settler colonial project you identify with to the ethnic cleansing of the colonized people.

Anyways I wrote this in part because it's useful for recognizing this propaganda as having a pattern and also in part because at a personal level you will certainly encounter people that treat you poorly because they are deeply embedded in this psychology and you can protect yourself and those around you by learning the signs.