Well, first off, there's Cartman always going after Kyle for being a Jew. Or the Passion of the Christ episode, where he organizes the South Park citizens for the "final solution." There was the "Jew Scouts" episode... And of course, let's not forget about the "Concentration Camp of Tolerance."
Did I leave anything out?
Mark
"Ike's Bris" and Kyle goes to yeshiva (that was the "Jon Edward is a Douche" episode)
He innocently dressed up as Hitler on halloween, not knowing what it meant and that people would have problems with it. The principal then had him watch a video on how "Hitler was a very bad man," after which Cartman admired Hitler.
Oh yeah, and the teacher decided to cover up his costume with a ghost outfit that came out looking like a KKK hood (the principal being as naive about that as Cartman was about Hitler), which of course freaked-out Chef.