I'm not sure how long it's been since people were allowed to have new kids in their underwear, but I don't think that feature corresponds too much with what Matt Stone and Trey Parker wanted to express long time ago with the episode Cartman joins Nambla. They satirized this group of people to make a point, and when I (very rarely) see eight year old new kids in their underwear (with other kind of features that may make it worse) it feels awkward.

I could be wrong, maybe it's a feature that was even requested by the South Park creators themselves, I don't know. People may think, "oh but this is South Park it's supposed to be this way, you are taking it way too seriously" well in my opinion not necessarily, because to my view they made fun of things but they also are serious about other things. Am I going too far? I don't know either, but I think we really could do without the few people who want to have new kids in their underwear. It is just a game, but I can't underestimate a potential influence.

Conclusion, dress up those few new kids in their underwear if possible please, lol (Sorry to some of the people for requesting this de-feature, not everyone with underwear new kids have any ill intentions).