No it isn’t, it’s a reference to a Perry Bible Fellowship comic https://pbfcomics.com/comics/skub/

(This one is sfw, not all of the comics are)

Even urban dictionary doesn’t contain a definition for skub as a slur.

I added one. It's under review. It's very self referential.

>Even urban dictionary doesn’t contain a definition for skub as a slur.

What about this then: https://en.m.wiktionary.org/wiki/skub

That literally defines it as a word from the PBF comic I cited? Nothing on that page defines it as a slur, just as a word used to mock people who argue about inconsequential things.

Seems I misunderstood the notion of "slur" as I'm not a native speaker. So now I've learned a bit ;-)

Isn't that a reference to a 10 or 20 year old web comic?

The latter, we're old.

Stop saying it! You're making it worse!