Errr, I suppose gay is alright, but I don't want to exclude lesbians and bisexuals and transgendered individuals, so I'll switch back to LGBT. May I ask Draugnar about your objection to the word Queer?
I think again this is the nuance you're not getting fulhamish. In this context truth =/= fact. Fact is that which is scientifically demonstrated as actually being the case. Truth is more complicated than that. Ultimately as humans, the things we believe and think, and even "know" aren't always scientifically and empirically, demonstrated. Knowledge is socially agreed upon. Now ideally anything that wasn't scientifically shown wouldn't be widely held and believed, but really, have you gone outside at any point in your life? Have you read a newspaper? Have you spoken to virtually anyone else in the world? That simply isn't the way the world works, and that kind of social osmosis is such an important way of creating beliefs and knowledge that we can't simply ignore it, (I'm not saying we should accept those things, just that we should pay attention to them). Relativism doesn't mean that everything is equally factual. Obviously that's nonsense. All of existence isn't just some enormous Schrodinger's Cat, both alive and dead, and yet neither, all at once. In different contexts many different, even contradictory things may be true, but only one such truth is actually correct. Do you see the distinction?
Draug is right, it's a figure of speech, for want of a better term, except that it differs from a figure of speech in that it's actually very important to at least some of the people who say it. Usually figures of speech don't have a lot of someone's self concept tied up in them, in this case they do.