I have some ideas on why straight people seem unwilling to accept queer people. I think it's a question of what do we mean when we say "accept"?
I spoke with Kitten Milk and he talked about there being two different ways to interpret "acceptance of gay/trans/other queer people". There's the kind of acceptance that is like:
"Gay people can be perfectly normal, I have a gay coworker. He goes to church just like everyone else, and he is a normal and productive member of society." --straight ally™

I think that this kind of "acceptance" can be harmful because it puts forward the idea that in order to be accepted, you must "pass" as normal. It is especially harmful to individuals who want to openly deviate from the norm -- for example, trans people who openly transition are visibly not "passing" as normal for at least some portion of their transition.
Or in Kitten Milk's case, he chooses to be outwardly effeminate, or in his words "faggoty".

The other kind of acceptance is accepting people who openly defy gender/sexuality convention, and I think this is a much stronger form of acceptance.
It is difficult particularly for many straight or white or cisgendered individuals because I think these people find meaning and order in the status quo which they have spent their whole life believing to be normal and amenable to everyone's needs.
You were talking earlier eht about how straight men treat women badly -- and many straight men would feel honestly very horrible and frankly unmanly if they believed that the male role in society was negatively impacting the women in their light.

It's much easier to believe that gender roles are "just how things are" -- why go against nature?
And I think that unless you're transgendered or have an important trans person in your life, you can go without thinking about the issues facing trans people for essentially your whole life.
So I guess in conclusion the reason many straight people seem so unaccepting towards trans people is that they believe accepting non-straight people means giving non-straight people the chance to adhere to society's standards by suppressing their sexuality, and trans people and otherwise openly queer people directly challenge these standards.