Here's my 2 cents:

I've had pretty good luck just asking T's over the phone if they're queer positive. I've stopped looking for them in pink pages type listings or even looking for people who write that they're queer positive on their website. I think it's usually pretty easy to tell early on when someone feels awkward about my being queer (or is actually homophobic) and just not go back. I mention this because this way i can widen my search and minimize my risk of the kind of awkward situation you just had. Plus I really just want a T who is skilled and compassionate and accepting and being queer is no guarantee of having those qualities. (Bonus: I'm rarely attracted to straight women, and have managed to avoid feeling like I'm in love with current T. I still want her to adopt me and that sucks but I don't know if I could manage also having romantic feelings for her as I've been there, done that and found it to be incomparably suckier!)

I did once do a phone interview with a gay T who did not have room for a new client immediately but we spent about half and hour talking and got into issues in some depth. I then found another T who could see me immediately and never ended up seeing the first guy. Fast forward two years or so and a mutual friend introduced me to a guy at a party. We had babies born a month apart and made plans to hang out at his house. Well when I got there he introduced me to his partner who was the gay T from the phone interview. I don't know if he remembered my name but I remembered his and felt pretty awkward!