I was amazed by this one. It makes fun of abortions and the tranny crowd(2 “sacred cows” for the Hollywood left). Warning, some of the language is a little rough-
http://www.southparkstudios.com/clips/104426/scramble-its-brains-or-vacuum-it-out
I remember that one, I loved how they showed that you don’t even have to be particularly religious to see the inanity of the pro abortion crowd. Basic common sense is all you need.
But that was from Season 9 -a very old episode by South Park standards, I don’t really know of an episode where they went after leftist sacred cows like that in the last 3 seasons or so , i.e. Seasons 14-16 or so.