You know, how is what Kyle goes through any worse then all of the main kids? Really the latest Kenny focus episode had him go through this whole arc about trying to figure out how he kept coming back to life, but only to be told the origin of some other super hero and still have to live with the burden of being immortal with no one realizing how constantly he dies ("Coon Vs The Coon And Friends"). Stan if he's not being embarassed by the ridicolous antics of his father ("Crepe Frache") is either the very annoyed straight man or having a problem that puts him in ridicolous situation ("Insheeption"). And Butters... if there was a specific butt monkey for the show, it would of been Butters for the longest time after he became popular, and it still happens from time to time (like "The Tale Of Scrotie McBoogerballs"). And let's not forget that Cartman does still get punished by either the hand of god or by others for his actions sometimes. So really how is Kyle really a butt monkey. Yeah sometimes he's ridiculed, embarassed or humilated, but before this episode was it any worse then any of the other kids? Hell thinking about it much crap as he went through here, Butters were literally forced to act like a dog, had a star stuck in his eye, pissed and crapped in "Fun Time With Weapons" so I think Kyle hasn't gone through the worst treatment in this show.
Well remember that worked too because of balancing it out with the boys plot. It also depends on what the joke is, how they present it and what the final resolution is. Really sometimes one jokes work but other times they don't and like I said this is far from the worst example. The last season premiere "Sexual Healing" did the whole one joke way way way way wayyyyyyyyyyy worse then this episode did.