He did not assert they were unknown: “We hit some new lows over the weekend with the MAGA gang trying to characterize this kid who killed Charlie Kirk as anything other than one of them,” Kimmel said in his Sept. 15 monologue.

I guess that leaves the question as to why Kimmel did not say: 'We hit some new lows over the weekend when people of all political stripes were trying to characterize this kid who killed Charlie Kirk as anything other than one of them'. Because that seems like it gives more information to the viewer because that is what actually happened and acknowledging people from both sides were doing the 'bad thing' should help to bring people together instead of driving people apart.

Correct! He never asserted what Mr. Robinson's affiliations were to begin with.

I added an edit after re-reading the comments.