I'm not entirely sure.
They did an interview for a broadcaster here in the UK where they were talking about their intense dislike for their home state Senator - a beer heir in Colorado I think. Definitely a Republican.
Maybe it was just him they disliked?
That was probably Pete Coors. Stone and Parker are pretty libertarian, which makes them very right on some issues and very left on others. I don't think they're the "anarhcy" brand of libertarians, though.
Either way, "South Park" can be fun to watch and "Team America" was hysterical.