When it comes to "cancel culture," most of the people doing the cancelling/boycotting are people who weren't consuming it, anyway. It's only a real problem for the person/act/show being cancelled when they get fired/lose their contracts, which only happens in instances where publishers/producers market to a wide-ranging audience and they're afraid that the cancelling/boycott will hurt their sales, like when Paula Deen lost book deals in 2013 because she admitted to using the N-word in the 80s. Her publisher didn't just publish her books, they also published things that pretty much covered anything and everything you could think of, and they decided there was a very real risk to losing more money to the impending boycott than they'd lose by not paying the publishing costs and just cutting her lose.

In South Park's case, the network knows full well what South Park is, as does their audience, and the show makes it obvious right up front that they're likely going to offend you. They took some real risks with the Scientology and Book of Mormon episodes, but the network itself is pretty well insulated from most of whatever legal action anyone can take (and Stone and Parker like it that way). Therefore, anyone getting upset at whatever they see there (and South Park has offended me more times than I can count, but I still watch it) have only themselves to blame for watching it in the first place, because that disclaimer at the beginning makes it clear that, "hey, we warned you." As a result, South Park doesn't lose a lot of viewers due to controversy.