That is one of my 4 all-time favorites.
The other three are the anti-smoking one that absolutely slaughtered Rob Reiner ("Sometimes lying is okay, like when you know what's good for people more than they do"), the first alien one ("Cows turn themselves inside out aaaall the time..."), and the one where Mr. Garrison tried to get fired for being gay (the boys being sent to the black and white Nazi "tolerance camp").
With that list, surely you've managed to miss the Barbra Streisand / Rob Smith episode. That one's a classic, is on my top 5 list for sure. Death Camp of Tolerance is so anti-Political Correctness, it's unbelieveable. One of my top 5 as well.
"Finger paint faster!"
My number one favorite, however, is the "Rainforest" ep, where the new hippie choir teacher (Jennifer Aniston) drags them all down to Colombia to save the rainforest which leads to the inevitable discovery that, far from being a magical place of wonder, it's a smelly dangerous hellhole inhabited by poisonous insects, man eating snakes and drug dealing gun toting rebels.
Oh come now! The one where he had that kid eat a chili made from his parents!