Re: Is homosexuality a social construction?
We'll probably never know, given the social complexity of humans. The fact is that our sexual desires and drives predate any culture, and our very idea of heterosexual marriage predates our written history and has varied widely over the course of our recorded existence.
We don't even fully know how naturally monogomous we are. I know this is one of Focoult's favorite arguments (then again he says the same thing about insanity) but the problem is we just don't know what those first folks stomping around in Africa about 100,000 years ago thought about a whole lot of issues.
Nature or nurture is almost impossible to separate.
Maybe I'm missing some of your points. There is enough evidence that supports LDV's point. It seems clear that rigid sexual classifications imposed on an entire population are - like race - entirely social constructs.
I agree with your point on monogamy - although there too there is enough data to infer that there is no "we are." The idea that humans are Borg is one of the enduring stumbling-blocks that arises from viewpoints originally instituted to "control the masses"
I didn't read LDV's OP as being about "born gay or not" (i.e. nature/nature) but about the instituting of rigid categories that people shunt themselves into. Without those constructs people would flow freely. Sure Pete may get it on only with other fellows but the whole psychology that has come to be associated with that wouldn't exist. If one day he met Mary and they both felt the urge - it wouldn't be a thing.
Mulder: "So you're agreeing with me?"
Scully "No! You're bat-crap crazy."
Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that. - Martin Luther King, Jr.