I'm using apolitical to mean disinterested in politics. Some people who are disinterested in politics call themselves libertarians because they don't want to get dragged into political fights they don't care about.

I wouldn't say South Park is apolitical at all: they have many expressly political episodes, which you don't do if you're disinterested in politics. They seem to be the type of libertarian who (1) is at least semi-interested in politics, (2) is disillusioned with both major parties, but (3) has not thought too deeply about their political stances beyond that.