I consider fighting words different from just being offensive/verbally abusive. If you're frustrated or angry and come off as offensive, that's VERY different from designing and structuring your communication around malicious emotions that have intent to hurt someone. Kinda like how accidentally bumping into someone you didn't see is nowhere near the same thing as full-body tackling someone to the pavement.
And this is just for example, so bear with me.
If I said "Wow wata scrub uninstall pls and refund dat skin" I would consider that VERY different from flaming someone in chat using racist, sexist, or prejudiced/bigoted language with malicious intent to hurt, like saying
" $&#% you you piece of %@$* failed abortion I hope your dog and mom get ran over in the street tomorrow and left to die unburied while you eat their **** and die crying at their rotting corpses 10 days later."
It's not that they're trying to place higher value on certain types of people, they're just delineating offenses by their egregiousness. Two different things.