Heh - well, I've had this conversation on other sites, where non-straight people have wanted to have a thread to 'come out', and straight people have taken offence and said that it shouldn't matter and that they don't care in the slightest whether people are straight or gay! So I did a post saying it doesn't matter if you're straight, but it does matter if you're not straight, because you are then the minority that everyone assumes is the majority. I don't think heteros realise how very hetero-dominated their conversations can be. And the gay pplz agreed with me.
I guess to use an example of a different sort of thing people can identify with - suppose you have a mental illness that people aren't aware of, and they assume you see the world in the same way as they do. You'd want to express who you are, and how things are different for you, so that people could understand. Or if you emigrate to another country where everyone shares a culture very different from yours, you might want to explain to them a bit about your own culture, so that they can get to know you. For the majority, the fact that they are not mentally ill, or that they are not a foreigner, has little importance to them, and they have no need to tell anyone, because it is an implicit shared identity - everyone already knows who they are and they have all kinds of shared understandings. But for the minority person, they have to actively explain who they are in order to be understood.