If you don’t actually look like the gender you are trying to be then they can get out. It’s creepy to everyone around them I don’t care if you put on a dress and call yourself a woman or cut your hair short and call yourself a man. You’re not. Grow facial hair then or get chest implants.
I’m telling you that the greek root has multiple meanings and use cases, sometimes fear (phobos) and other times anxiety or repulsion. Our modern definition of “a phobia of something” does indeed include fear. But trying to generalize that over to the word transphobia in order to pretend it’s not a real thing is just silly. None of the words xenophobia, homophobia, hydrophobia, or transphobia have anything to do with fear, just repulsion.