At least by my reading, I'm willing to concede that it isn't about gay people explicitly (Leviticus has enough to say about it anyway). But anyone that tries to argue it's only about a specific kind of sex act ("bottom role") is a retard.
In broad strokes, the story's about whether Sodom and Gomorrah has at least 1 upstanding person. Upon having visitors from Heaven itself, they not only show inhospitality toward their guests, but want to actively fuck them. It's supposed to show how beyond hope they are, and that it's understandable why God nukes them from orbit.
I'm willing to (partially) agree with his interpretation that it's more about inhospitality and being sex pests, but how on earth do you turn around and say it's a specific sex act?