Cartman is Trey and Matt’s favorite character, so, it’s understandable that they want him to be the star of almost every single episode.
However, in the games(most notably South Park: Stick of Truth), we see that Cartman is ridiculously nice with the New Kid while Kyle is terribly mean to him, look, i don’t care if was because the New Kid was Cartman’s ally, but this was pretty much a dick move of the creators to depict Kyle as this tyrannical boss.
Since Cartman is now a benevolent boss and the fan-favorites Kenny and Butters are in his team, it’s much easier for the player to choose side with Cartman and the fact that Kyle only appeared in the middle of the game, certainly don’t help.
The problem is that there’s no healthy bond between Kyle and the New Kid, it’s also strongly implied that Kyle is only using the New Kid to compete with Cartman.
And this is kinda out of character.
I know Kyle was shown to be a jerk before, but he’s the only character to not really care about the New Kid’s safety, he’s just being an asshole to him and doesn’t give a shit about him getting hurt.