Aristotle: You are arbitrarily saying the only part of the marriage equation that can be argued is the sex of the participants.
The scope is specifically gay marriage. People DO argue for polygamy, I would never deny that, and there are cultures where polygamy is the norm (duh). I assumed I could speak using generalities to some degree, to avoid enormously long posts, and it would be acceptable.

I've never, and will never argue in absolutes, I just don't operate that way. So, SOME people do use these arguments in favor of polygamy, I'm sorry if it sounded as though I was denying that.

What I'm saying is that there are other parts of the marriage equation, and they're not intrinsicly connected.

Aristotle: There are entire cultures where polygamy is not only socially acceptable, but considered a social good.
You are 100 percent correct. But, we're talking about American politics (again, not dealing in absolutes, there are pockets in America that WANT polygamy.) where polygamy, is by and large, not socially acceptable.

Aristotle: Being homosexual may not be a lifestyle choice, but being married to someone of the same sex is definitely a lifestyle choice.
Well, this sounds like the school of thinking where marriage is a privilege. And, it is. However, EVERYONE should be able to enjoy the right to obtain this particular privilege, regardless of who their biology tells them the sex of their partner should be.

Aristotle: Only because you are arbitrarily choosing to declare them not the same.
Homosexuality is not a choice, and if everyone should be able to obtain the privilege of marriage by right: it's not arbitrary in any way at all to include the fact that homosexuality has biological roots whereas polygamy does not as the crux of my argument.

To be married is, indeed, a lifestyle. But, according to the constitution, we have the right to pursue our particular lifestyles: now there's an argument for polygamy. However, I was drawing a very stark distinction in that homosexuality isn't a lifestyle, but a biological occurence, and should then have protection under law on that very basis.