I think the problem with South Park is that some don't take the show in as entertainment, but rather a basis for their own morals.
I see this a lot on Reddit. There's people that watch South Park, because they enjoy it as entertainment, but there's also a good number of people that take it to heart. Rather than formulating their own opinion, they just copy and paste from that show, or the works of other comedians. I've seen people try to defend the use of the word 'faggot' solely by linking a video of that Louis C.K. bit, without any extrapolation or qualification. For every person that's used them to see an issue from a different perspective, there's a good number of people that just go, "Yeah, that totally makes sense," and moves on - not bothering to really think about what was said.
It's good to satiric or comedic works to see another side of the story, but it's not a positive action to justify them without any other sort of criticism.