Didn't Trey and Matt literally come out as Republicans like 15 years ago?
Anyway,
every character on South Park is a caricature, that's half the fun. What, are PC Principal, Trans Randy Savage, Mr. Kim, or Kyles dad who transitioned into a dolphin all completely normal everyday people to you?
"Lel ecksee conservatives can relate to cartman while we enlightened liberals can relate to everyone else!" is an opinion only someone who has never watched the show could have. Fucks sake half the cast on the show are drug addicts or murderers, outside of having a more annoying personality Cartman fits in pretty well.
The overwhelming majority of people who like Cartman or the gags involving him do not "relate" to him. He's an evil, annoying little shit that manipulates, tortures and kills people on a regular basis and that's part of what makes him funny. He's a horrible person in every way, and he is regularly punished for being so. When he became Hitler and worshipped Mel Gibson the episode ends with Mel Gibson literally shitting on Cartmans face. But the show also
validates Cartman, and yes even his racist opinions, all the time for the sake of being funny.
When Cartman sings about the waterpark being full of minorities and them ruining it the joke isn't just "Oh Cartman being racist again oh haha how silly and unliberal of him!", the big followup joke after Cartman's song is literally about the minorities overwhelming the park and pissing in the water so much they destroy everything by causing a giant piss tsunami.
When people call South Park "le based" for making offensive jokes it's not because "Ah yes clearly Cartman is the hero. He is so literally me and I agree with everything he says" it's because the show isn't
afraid of being offensive with it's jokes. It's not afraid to shit on obnoxious progressives or use racial stereotypes or use offensive gags for the sake of being funny, and in doing so
it's also not afraid of making someone as awful as Cartman correct for the sake of humor.
That's what makes it based.