Why Does Chris Matthews Insist on Making Golden Showers Jokes About Trump?!?

A largely discredited dossier was circulated earlier this year that alleged President Trump had participated in golden showers (sexual urination) with some women in a Moscow hotel room. He and his spokespeople have consistently denied this. But some in the media are so hung up by this notion.

MSNBC's Chris Matthews has dabbled into this misleading news story before, but now is outright joking about it. He said that Trump needs senators on his side right now as he tries to get his legislative agenda passed through Congress, especially the Republican ones, but that "he has just peed on three of them." Insert laugh line here?

Also watch this Stephen Colbert video. Why do they insist on making baseless references about our president?!? There are actual debates we could be having about Trump policies, but the ad hominem attacks do nothing for their side or ours.