I think you're being a bit naive. While it's true he's not shouting over someone, he's using a very different but equally obvious tactic. First of all he is not disagreeing with an opinion someone has, he is disagreeing with the basis of their identity and human experience. However polite, that is rough to deal with without getting emotional. He is knowingly attempting to be deceitful. Trying to play the nice guy, but hand picking "studies" and misrepresenting facts. Notice how he's switching between a biological argument and then going straight to solipsism, nevermind that studies show there is in fact biological differences that pertains to the way we view gender and sexual identify. When he asked "How do you know you were born trans?" and the guest applies "How do you know you were born heterosexual?", he had an answer obviously being that he has male hormones and like women (which is very simplified and may not be entirely true, but that's another thing). What she should have asked would be "Why do you like certain type of features in women, over others? Why do you like the color green more than blue?" to make him consider why that is. I'm not saying that liking a certain color or liking redheads is the same as being attrackted to the same sex or identifying as another gender. He was trying to paint her as a solipsist without reason, or more bluntly put, a nutcase. She should throw that back to him, because what I am saying is that it's more complicated than you'd think and the science backs that up.