I don't know why anyone would prefer the term "Queer" over the other terms, because "Queer" means weird, strange, or different. I do not on any occasion, view my liking of other boys strange or weird. Sure, it's different, but it doesn't make us WEIRD. @_@
I think the fact that it means "weird" is part of the point of why some people like it. I think the use of the term among has partly just filtered down from the ivory tower as the development of "queer theory" in the academy picks out a distinctive way of looking at sexuality and gender. I don't know much about queer theory (despite numerous classes in which I was supposed to be figuring it out
--though I think that's kind of its nature to be hard to pin down), but from what I understand the emphasis is on understanding gender and sexuality not as real aspects of reality, but as things which are continually constructed through language and power. Attention to sexuality is also more broad than just glbt issues--sex work, pornography, and S/M are understood as constructed "deviant" identities along with sexual orientation and gender.
In activist circles I think the word is often embraced for practical reasons as an umbrella term meaning "different from the heterosexual norm." Since there are so many identities which most gay-related activist groups want to include (and the list just keeps expanding) it's just impractical to list them all out with a letter.
Plus, often individuals feel that they don't necessarily easily fit under a certain letter--G, L, or B--especially that the letters reify the false idea that there are two and only two sexes and that all human beings fit into one or the other of them and that a person's sex is fundamental basis of attraction for all humans. (I personally have issues with this. I identify as bisexual mostly for ease of identification, but I don't like the word since it essentially means "attracted to the two sexes." But I don't believe that sex is a dichotomy. Nor do I feel that I'm attracted to people as a result of their sex. It's actually the opposite. I'm attracted without regard to sex. Kind of like I'm attracted without regard to hair color or income level.)
I think a lot of this also has to do with assimilationist vs. liberation politics amongst glb groups/people. Assimilationists tend not to want to rock the boat regarding the categorization of sex, the acceptability of certain kinds of sexual activity, or the institutionalization of monogamy and marriage. The idea is just that society was wrong in constructing glb people as deviant, but non-monogamy, rejection of marriage as an institution, S/M, etc really are deviant so they can legitimately be rejected. (This seems like the kind of thinking which one sees in the "Why I Won't Go to Gay Days This Year" essay that is available through the DIS.) The end goal for glb people is "gay rights"--the right to marry and all the rights that go along with it, the right to respect for one's long-term and monogamous relationships, etc. Liberationists, on the other hand, can see how important it is to get these rights, but there is concern that in order to gain the rights glb people have to assimilate and become like straight people, thus giving up what was revolutionary about their movement and thus betraying others who will still be marked as sexual deviants. It's actually a really interesting thing to think about. GF and I tend to be wary of too much assimilation and generally mistrustful of marriage as an institution, and yet we also feel the pull of the practical necessity of assimilation in our daily lives. For example, same-sex partner benefits have just been banned in Michigan (where we live) which means (unless the case is overturned on appeal) GF will no longer have health insurance through me
