I actually stopped watching the show for a couple years for that very reason. I'm pretty cynical about the current state of our species, so can find amusement in the show's commentary on how things are right now, but am ultimately fairly optimistic about how much potential we could have if we ever chose to act on it, so can get annoyed by its snarky nihilism.
I've come back around to embracing the funny, and have since watched all the shows I missed during my hiatus, but there are a few episodes I still just really don't like. And I'm still particularly annoyed by Parker/Stone themselves. Having the stones to challenge various systems and structures is great, but when it comes to the point you're ting on a lot of the people who have helped you out (the temper tantrum over Isaac Hayes quitting comes to mind) and the very system that has provided your fame/wealth/voice/etc. without ever acknowledging the privilege you receive from that system... There can be very fine line between social criticism and a whiny brattiness.