I'm going to call someone racial slurs for being an asshole.
Why use racial slurs?
I want to hurt them for the way they treated me.
As badly as they treated you using racial slurs is never okay. You have to find a way do deal with this person that doesn't involve using derogatory language.
I can do it if I want.
Just because you can, that does not mean you should. Racial slurs are insensitive and there is no reason to retaliate with words.