Only to people who don't know or, in this case, more likely, don't care about the distinction. It's to the level of equating lesbian with bisexual. On this particular occasion, I got a heads up from a friend that Lambda had to be argued into even including a trans section at all, so.

There has to be some good stuff out there but I can imagine that it's mostly skewed towards coming out/realising you're LGBT stories. The classic stuff seems like it might be skewed towards the tragic gay love story angle if things like Giovanni's Room are anything to go by. Even historical fiction (fanfiction example but very well written) seems to go down the route of focusing on all the historical barriers mainly, and of course female homosexuality simply flies under the radar (unless you're talking about those Sarah Waters novels, which I can't stand). As for more modern novels, I recall reading Aidan Chambers' Dance on My Grave when I was in high school but I honestly can't recall that being terribly deep anyway.