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I'm not defending Trek's bad record with gay characters on tv and movies, but there are a few positive examples of acceptance and a handful of sort of gay characters.
It's implied that Jadzia Dax is bisexual. She has a relationship with Kahn, whose symbiote's previous host was in a hetero marriage to a previous host of Dax. It's based on a past hetero relationship, but the two women want to be in a relationship and are only stopped by the severe penalties for the taboo of their society, which is reviving a relationship from a symbiote's past. Years later Worf sees another woman (played by Vanessa Williams) as a romantic threat with Jadzia, more evidence of Jadzia's bisexuality. It's open to interpretation though. Nobody was more disappointed than me that Trek didn't have a more directly realized gay character, but they were different times. The new movies have continued to fail in this regard and I can't defend that.
Kira is completely supportive of Jadzia's relationship with Kahn, and years before that Jadzia was supportive of what she thought was a male Ferengi in love with Quark - which wound up being a female Ferengi passing as male because of the oppressive sexism of Ferengi society.
For all it's failings, I think Soran's speech about the oppression she's faced and the difficulties of her life are very touching and a clear parallel to the plight of gays. Riker's defense of her is powerful. I think it's important to acknowledge the strengths of the episode as we have explored the weaknesses of it pretty well. I can tell you as an out young gay man at the time this came out, it meant a lot to me and other gay Trek fans. Trek failed us by not doing more, but at that time this was still pretty groundbreaking.
There are a lot of gay characters in Trek lit, including main regular characters in series like Titan, New Frontier and Vanguard.