Put it this way, phobia comes from the greek word phobos or fear. Phobia of flying means you don't like to get on a plane, an actual physical reaction to something as a human you fear on an instinctual level.

The gays have tried to take phobia to mean fear of gay people, but there is no fear over people who butt fuck each other or cut their dicks off. So remember, when they say "Transphobia", they're projecting because it means people fear them not you fear trannies. It's just a buzzword also.