Not sure I follow your point. Interested though, care to elaborate? I have not seen the musical.
Everyone got very excited about south park after the Team America movie, which contained blatantly conservative anti-islamist themes. And in the following seasons of south park (9 & 10) they carried on with some conservative issues such as anti “global warming”, and everyone was very excited about that.
But they got a lot of flak from people in LA. The turning point was the episode “Mystery of the Urinal Deuce”. The original soundtrack had a Bush voice that was sympathetic to him. In reruns and the DVD, they have changed the voice to nasty cowboy. It’s the first time they ever changed a major thing about the show after it aired, and it represents the point at which they caved to the liberal voices around them. And it just got worse from there. Their most recent episode was very negative about the Tea Party.
So I’m not surprised if their musical contains points that leftists would use to bolster their argument.
All good things must come to an end.