Genuine fear is one.
Fear of not being socially accepted or abused (physically or mentally)
If we all flocked together they'd call it a staged event, on our own we are sissy boys or trannys.
It's a scary old world out there and whilst I can only speak for myself, I am very sensitive and cry easily and to be abused like that would be so hard to cope with.
That said the tg community is creeping up in acceptance. Mainly amongst the younger generation, but that's a good thing