I dunno. What SP did to the Mormons was really leveled at the foundations of their faith and not any kind of hypocrisy. How many times did they say Mormons were “dumb, dumb, dumb” for their beliefs?
To be fair, you can’t nitpick parts out of the Mormon episode without the context of the resolution dialogue:
Stan: You guys were right, okay? The new kid’s a douche. Now I just gotta find a way to keep him away from me.
Gary: [shows up] Hey Stan.
Stan: Oh brother.
Cartman: Uh oh, the jilted lover returns.
Gary: Listen, I just wanted to let you know you don’t have to worry about me tryin’ to be your friend anymore.
Stan: I don’t?
Gary: Look, maybe us Mormons do believe in crazy stories that make absolutely no sense, and maybe Joseph Smith did make it all up, but I have a great life. and a great family, and I have the Book of Mormon to thank for that. The truth is, I don’t care if Joseph Smith made it all up, because what the church teaches now is loving your family, being nice and helping people. And even though people in this town might think that’s stupid, I still choose to believe in it. All I ever did was try to be your friend, Stan, but you’re so high and mighty you couldn’t look past my religion and just be my friend back. You’ve got a lot of growing up to do, buddy. Suck my balls. [turns around and walks off. All four boys just look at him in wonder, even Cartman.]
Cartman: Damn, that kid is cool, huh?