Maggie's Farm

"When Kinsey started the fire, most resisted the idea that sex should be entertainment, until pop culture normalized it."
I beg to differ. Prostitution is known as "the oldest profession" for a reason. People have engaged in sex primarily as entertainment through most of our history, as far as I can tell from Pompeii's wall paintings to the stories of Baudelaire to the wide availability of porn on the web. People have always wanted to have sex with pleasure and not consequences. Kinsey may have helped it along.
As for polygamy and sexual anarchy: nope. Polygamous societies are often among the most restrictive for sexual activity outside of marriage. And polygamy itself is a practice seen throughout human history. That doesn't make me an advocate, I just want it evaluated on the facts.
Marriage for homosexuals should be a stabilizing influence for them, not a destabilizing influence for others. There may well be advocates of polygamy and gay marriage who hope that those practices will break down traditional marriage. I'm pretty sure they are wrong, though.

Howdy GoneWithTheWind
I was going to skip your point, but okay.
Yes, I agree -- if states are to recognize the relationships of two men and two women, they ought to recognize any consensual contract among adults. Polygamy, polyandry, three-and-two-and-pick-them. What business of mine, as long as all the parties have made knowing choices?
In many polygamous societies, including some of the below-radar American practitioners, the practice does seem to involve a level of coercion on teen girls to choose to be junior wives and a corresponding casting-off of teen boys. I call that a problem, but it's based on the coercion issue rather than who wants to share a family with whom.
I haven't heard a cogent argument for marriage involving animals. I would say that animals simply don't have the social construct for contracts with humans. I will also acknowledge that sex with animals goes past my "ick"meter because I doubt the animal is a willing partner. It also exceeds my general "ick" meter but my "ick" meter is not a basis for legislation.

Howdy Mudbug
I'm a libertarian as my first take on almost anything -- I know your name from the blog and I'm sure you knew that about me. I've become suspicious that some people who say they want to "defend marriage" are inclined to grant very little latitude to other relationships at the law. Of course I'd be wrong in some cases.
"Perceived benefit to society" is a very, very squishy basis for legislation, as the other thread on individual vs legislative golden rule points out. It might be of benefit to society if all kids learned to play the clarinet or some other instrument -- but I'll be darned if I'll let that be legislation. It might be of benefit if all kids learned to shoot firearms, too -- and how loud would that howl be?
The business of government is to maintain order and safety, and (to a degree) to promote commerce. THat makes law enforcement and firefighting legitimate, road building almost certainly, charity very fishy. Even public education, or subsidies for education, could be opened up for debate on principle. But I'd better be careful on that one: my entire education was subsidized by taxpayers.