I just heard about the south park episode that makes fun of scientologists was taken of the air, not banned excactly, not anything that official but as good as, and besides in america few things are actually banned now because of the constitution, their just taken off the air by whoever owns the station that their on, nothing to do with the goverment at all.
Allso do you know that rage against the machine's entire back catalougue is still banned by clear water america's biggest comercial radio network.
But to get back to south park considering that in previous episodes they have suggested that jews worship moses and that chatholics worship a giant space spider i can't imagine what they said about the scientoligists that could be worse than that. Having said that i do see it from their point of view as well they get huge amounts of bad press often for little or no reason rumours passed around by knews networks that have little or no understanding of this relegion people who say that its a cult because they don't have any gods without realising that by that theory buhdism would also be considered a cult, all i can say is that this isn't the best way to go about defending you're self, its not even in the top twenty.