the "held comments" feature on youtube algorithmically hides comments it deems inappropriate if that feature is turned on and it's left to the review of the creator. I'm not sure if Joe Rogan has that turned on or not, but to accuse youtube of biased political censorship you'd have to actually show explicit bias towards the content.

I feel unless shown otherwise (and I'm not really keen on spamming random hate speech into youtube comment sections), I'd assume that slurs like that may have been caught in some generic filter.