A significant fraction of the US public--and certainly a majority in certain demographics and regions--is utterly opposed to same-sex marriage, and in many cases to same-sex anything. Some deny any personal animus to gays and lesbians--disapproving of homosexuality and bisexuality in the abstract, while practicing tolerance towards individuals--whereas others are openly hostile to a minority they view with contempt and disgust. Many on all sides of debate have attempted to explain the strong feelings that many people have considering anything gay, and numerous justifications and rationales have been offered up--religious teachings, appeals to "nature", revulsion towards "the act" (or acts) involved in homosexual coitus, a necessary coupling of sex and childbearing. Less flattering justifications include power politics (certainly a few political operatives see gay-bashing as their road to office), male insecurity, and just plain bigotry and nastiness. Probably all of these have some kernel of truth to them, and depend on who you ask. But... I think there's more.
Opposition to homosexuality, after all, is found in many demographics, not all of them white and evangelical. Quite a few homophobes aren't religious at all; for others, Leviticus is the only part of the Bible they can recollect. Anti-gay attitudes can be found in almost any fraternity house or locker room. I've met many homophobes whose own sex lives, while straight, were definitely not narrow--folks who denounced the immorality of gays and lesbians while playing the field like sailors on shore leave. In short--people who oppose homosexuality on some grounds--but none which they can articulate without looking like complete hypocrites.
But in many cases, I think I know the answer: They view gays... as vampires.
Not literally, of course. But a significant part of the population seems to view homosexuality as an acquired terminal condition which is spread by hostile action--akin to vampirism.
The origin(s) of human sexuality itself is a subject of debate within the larger debate. Biologists have long observed homosexual behavior among animals, including specimens which appear not to mate with the opposite sex; this inclues many species for which neither physical pleasure or emotional attachment is a relevant concern. Many (on all sides) consider the nature-vs-nurture-vs-choice question to be highly relevant to how society should react, and how this reaction should be expressed in cultural and legal norms. Supporters of gay rights have long supported the belief that sexuality is a matter of biology; whereas opponents have long referred to it as a "lifestyle choice", akin to the choice to drink alcohol or not. Obviously, it is harder to justify legal discrimination considering a characteristic which is involuntary.
However, there is yet another theory, which is seemingly popular in some circles--it is what I'll call the "vampire theory of sexuality". This theory is seldom defended in any serious academic forum, and as far as I'm aware there is no scientific evidence for it whatsoever. But it is a popular meme, and one which explains, I think, the strong reactions that some people have to gays. The theory goes like this:
- The natural state of humans is heterosexuality. People are "born straight", and barring any event as described below, will remain that way for their lives.
- Some small percentage of the population, however, is not straight--the origins of homosexuality and bisexuality aren't always addressed, but aren't really relevant for the theory.
- The gay population--rather than simply forming relationships among themselves--needs to find new members to be sustained, much as vampires need to find new victims to feed on. Thus, they actively "recruit" among the straight population--looking to seduce young (and often unsophisticated) persons, and get them to "try" homosexual acts.
- A significant fraction (not all) of those so seduced find they like it. It is at this moment, as a result of this act of "seduction", that a person becomes gay (or bisexual). According to lore, one who is bitten by a vampire becomes a vampire themselves; and so it is, according to the meme, with homosexuality.
- Once so converted, they immediately start looking for other "converts" to recruit, in order to further perpetuate the cycle.
- Gay political activism, gay rights, SSM, and all other things collectively derided as the "gay agenda"--is not done so that gays can live their own lives in peace--it's to permit the "cycle of seduction" to occur in the open, and to frustrate attempts to oppose it.
This meme is, of course, utter rubbish. As gay people come out of the closet and interact openly with the straight population, many of the rumors and lies which underly the "gay vampire" meme vanish--people notice that openly gay persons aren't hitting on their straight acquaintances, and in many (most) cases are living in monogamous relationships with a committed partner. But for those who DO believe in the gay vampire meme (especially those whose view on the subject is intermingled with a belief in an supernatural malevolent entity bent on wrecking the world--Satan, for instance), the advancement of gay rights isn't just an annoying development in the annals of civilization--it's a direct threat to civilization's survival. Which is a major reason, I think, that the opposition to SSM has been so fierce.
And helping to drive a stake through the heart of the "gay vampire" meme is one reason why SSM is so important.