Weird, somehow I’ve never heard of this species or seen one in another Star Trek series. From a cursory internet search that might be because I’ve never seen Star Trek: the Animated Series.
A big part of science fiction is how fictional technology and environments of the future that would seem very strange to us are completely normal to them. I agree that this should also extend to society itself and its speculative future progress. In the same sense that a character wouldn’t find a replicator to be strange technology it wouldn’t make sense to treat someones sexual orientation or gender to be strange if it is a social issue that was supposedly a thing of the distant past. I find that a lot of 21st century social issues seem to find their way into modern Star Trek in ways that don’t make a lot of sense.