One thing that perplexes me about some (not all) usage arguments it their insistence on assigning One True Inherent Meaning to a particular word. "Ten times lower than," the argument goes, is wrong:
The words "times" refers to multiplication. Ten times a number is exactly that. Your usage is simply wrong. Your meaning therefore is vague and the sentence plainly ridiculous. It cannot be. Such usage indicates an inability to think clearly. You are wrong.
Lots of "cannot"'s and "wrong"'s, but it all rests on the assertion that "times" must refer to multiplication and only multiplication. Yet the word "times," as the dictionary shows, has lots of meanings. That it means multiplication in some situation doesn't mean that it somehow must inherently mean that everywhere. (Of course, one could argue that using it to mean something else may be confusing; that's a separate argument, which I've engaged elsewhere on the merits -- here I speak only of the One True Inherent Meaning argument.)
The same arises, I think, in some (again, not all) arguments against same-sex marriage (or for that matter against "unnatural sex"): Marriage is inherently about one thing, namely procreation, and therefore same-sex marriage is somehow inherently a violation of the fundamental nature of marriage:
Marriage used to exist for one reason. It was a contract between a man and a woman. The woman promised the man that any child she had would be from his DNA, the man promised to help raise and protect the children and to provide for the family. That was it. It wasn't about "love" or "acceptance" it was a financial contract. That's why at one time brides had to have dowries, to basically purchase their husbands, or the husband might purchase the bride, depending on the culture. (basically its built out of the inheritance rights.)
Ist true, that now with most work not requiring a lot of physical strength and endurance most women can do as well as the average man in making money, but that doesn't change the social impacts of not having a mother and a father while growing up, and sadly the "free love" of the 60's has caused to many people to forget that important part of the marriage contract.
So to me being against "same-sex" marriage, has nothing to do with bigotry. It has to do with understanding the cultural realities that created the sacrament of marriage, and the pure evil and cultural nihilism required to attempt to mutate that contract simply to force acceptance of homosexuality.
If one is really looking at what marriage "used to" be as a guide to what it must be, one must also consider that marriage often used to be a contract between a man and several women, or more likely (as the commenter I quote above acknowledges) a contract between a man and several women's fathers. But, in any event, for centuries marriage has also often been about love, about company in old age, about emotional tranquility, about sexual hygiene, and more.
I would think that this capacity of marriage to serve the other valuable functions is a sign of the strength of marriage, not something to be minimized or condemned. We wouldn't find it repulsive when post-menopausal women marry. We wouldn't find it a sign of "pure evil and cultural nihilism." Rather, we'd dance at their weddings, and appreciate the value of the marriage both for the parties and for society. Same when we see the marriage of people whom we know to be infertile, either because of disease or because of deliberate choice. Such a marriage is an occasion for joy, not contempt or concern about the erosion of the One True Inherent Nature Of Marriage.
Once we acknowledge that marriage can therefore have many functions, what's so "pure[ly] evil and cultural[ly] nihilis[tic]" about extending to marriage to couples who are unable to reproduce because of their gender, rather than because of their age or because of some medical condition? Of course, one could make other criticisms of same-sex marriage. I'm ultimately unpersuaded by these criticisms; but at least many of those criticisms focus on plausible speculations about actual effects, rather than on the supposed One True Purpose of an institution that -- like many successful human institutions -- serves many purposes.