There are no real reasons to be phobic of anything.
I’m a little phobic of spiders – to me its because they tend to climb on my face and run across my body before disappearing into the abyss that is my bedroom…
My parents were phobic of my being genderfluid, probably because they didn’t understand it, it was a new concept and to my father it still is.
Why are some people homophobic? Because they don’t understand the concept? Because they’re affraid they may be Homosexual?
Why are some people transphobic? Because they don’t understand it? Because they think they may be themselves?

There is a different reasons for everyone but until we can educate people, these things will not stop….

No one should be affraid of humans.