DISCLAIMER:This joke is homophobic. "Trump being embarrassed for people thinking he had a gay relationship makes him homophobic. Affirming that embarrassment by making it the butt of the joke makes the joke homophobic"
this article explains it well: https://newhumanist.org.uk/articles/5082/the-dangerous-stereotype-of-the-self-hating-homophobe
Also, it's not homophobic to say that homophobes being gay on their private lives, especially if they work to pass policy that makes it worse for gay people, are bad people. It isn't about them being gay. It's about them enjoying a thing while trying to punish others for enjoying that same thing.