The message: Scientologists are saying you can make fun of other religions....just not theirs!
Isaac Hayes was fine when they mocked other religions, but when they hit Scientology, forget about it. He's taking his voice and going home...Hayes quit South Park over their "inappropriate ridicule" of religions. Matt Stone, co-creator of the series, is quoted in the above article as saying, "In ten years and over 150 episodes of 'South Park,' Isaac never had a problem with the show making fun of Christians, Muslim, Mormons or Jews..."
It seems that fundamentalists of all ilk are prone to hypocrisy, even Scientologists.