A big part of that being that being LGBT entails being things that actually exist, even if there are people who fake being so for various reasons (political lesbians, transtrenders, the "I'm bi" trend in the mid-2000s, etc.). All the other extra-fake shit (genderqueer, demisexual, aromantic, etc.) started up only recently.
Alright, dumb question, what the hell is a "quierosexual?" I've heard of "lithoromantic," which is still retarded as shit, but I'm guessing the other term is a newly made one within the past few months? (I tried googling it and got nothing.)