And this is an episode Matt and Trey have been working on since before Assburgers, so as a month-old script, it couldn't be too timely and heavy in case the Wall Street situation changed before the episode was even finished.
I would guess that a month ago it didn't have any Occupy stuff in it at all. I think it even had a different title, then. I would imagine they added the OWS stuff closer to when it actually aired, like over the last week basically.
Seems South Park's going through a bit of a Moral Orel phase at the moment, sort of deconstructing itself every chance it gets.
On the 60 Minutes special it was called "Crapped His Pants." So it's possible that the plots of Bass to Mouth and 1% were actually mixed together.