I saw it last night too. It was pretty funny, but I think they are a little too harsh on PETA. The vast majority of PETA people aren't anything like that, just like the vast majority of pro-lifers aren't going out and bombing abortion clinics. Also, I have to take issue with their thinly veiled charge that both candidates suck, or the similar there's no difference between them argument.
It would have been a lot better episode (but probably less funny) if they had gone with the angle that the amazing, wonderful thing called Democracy that they teach you about in school really doesn't work very well in practice, and that most of your life you're going to be voting for people who don't match your political views very closely because the other candidate is evil/stupid/ignorant/elitist/pick your favorite reason.