This guy just keeps getting more and more of my respect. He seems to get it. People aren't threatening to you unless you feel insecure enough about yourself that you make them threatening to you. We are tribal as a species. have been since we came out of Africa. If you aren't in our tribe, you're a threat. No matter what we've done, how much we've learned in the thousands of years we've been here... we can't seem to shake this caveman mentality in a lot of people.
"If someone's happy, why is that threatening to you?" This sums it up. It's the most pertinent and seemingly unanswerable of questions. From what I can gather where I live... it's threatening to men because it makes them question their masculinity, and it's threatening to women because it makes them question their femininity. It just makes people look at who they are when they see people who don't fit into the mould society has made for everyone.
It's insecurity. Pure and simple. But that isn't the fault of the trans person for wanting to be themselves. Don't hate someone for making you look at who you are. That isn't fair. We all just want to live our best lives.