> I know full well what the question was, and you responded to it by saying that some forms of slavery are OK. Not sure what forms those would be, while still being 'slavery' for every reasonable definition of it, but still.
Ok, let's look at Rome for example. The reason I find Roman slavery relatively non-objectionable is a combination of a couple of factors:
1. Political incentives by owners to free slaves (i.e. freedom alters but does not obliterate mutual obligation, and therefore freed slaves are valuable to a household). Over time this meant that a relatively large percentage of slaves would be freed within their lifetimes, and their children would grow up to be citizens of Rome.
2. A major source of slavery was in essence an exchange of a subsistence guarantee for a loss of autonomy. This is not different in kind (though it is in degree on both sides of the equation) from the modern relationship between salaried employee and his or her employer.
3. The loss of autonomy of a slave in Rome was less than it was in many other societies. Slaves could and did belong to professional organizations, for example, and many of these had rules about how to conduct funerals of a slave member if the master failed to deliver the body.
4. There were legal restrictions which highlight some of this. For example, a father could not sell a given son into slavery more than three times (see the Twelve Tables). Such a rule would make no sense if slavery was less constrained.
The result there was a sort of revolving door between slavery and freedom and it meant, effectively, that abuses of slavery could and were politically controlled. This is fundamentally different than in the US where slavery was between racial groups, there were no incentives to free slaves and so forth.
> "What does that even mean?"
Very simple. If it is a cultural norm to retire with the kids, then parents have an interest in their children marrying someone that they can quite literally live with. Parents will find ways of making this interest stick on their side. For example, arranged marriages may be a part of that in some cultures, and in places like Indonesia, parents get an effective veto over a marriage license. This makes sense to some extent because parents are parties which are fully invested in such marriages, and therefore really are parties to the marriage.
However, at the same time, honor and image matter. Consequently, parents will yield on vetos (or hasten to "arrange" marriages) where this ends up not undermining their larger political interests in society. This means, effectively that "look-- they are bad parents. Their son got so-and-so pregnant...." or "their daughter got pregnant and was abandoned" are very much against the parental interests. Therefore "accidental" pregnancy is a way to coerce parents into going along with a preferred match even if the conventions are arranged marriage or a parental veto.
This veto override is solely the product of heterosexual reproduction and therefore is not available to same-sex couples.
What I am getting at is that same-sex marriage may indeed follow from (and I think probably does follow from) modern American ideals and functions of marriage. However those are both modern and American, and older models have very different dynamics attached.
> (I can't believe I'm actually replying to this, it's like arguing on stormfront.org)
I think the difficulty is that as an American who has now lived in Indonesia for two years (and has always loved reading history including for example Plutarch), my cultural assumptions have shifted a bit. The problem with arguing where assumptions are not shared is that all too often the assumptions are determinative and therefore it becomes impossible to argue without running into that problem.
But since I mentioned Plutarch, I am going to mention one other huge assumption that is usually made in these debates, namely that the choice is between oppression of people who prefer same-sex relationships for whatever reason (and to be honest I don't think the reason matters), and full equality up to and including same-sex marriage.
The problem with this is that it assumes that identifying with sexuality and sexual preferences it itself universal, but this isn't really fully true (for example see Foucault's "History of Sexuality"). Identity and how it relates to sexuality is a very complex thing, and culture forms a large part of the gap. It's worth remembering that as Plutarch portrays Sparta, pederasty and wife swapping formed functional political institutions (though the former would almost certainly have been heavily constrained due to Greek concerns about sexual abuse, believe it or not, something Aristotle discusses a great deal in Politics, and there's no real reason to think that Sparta had a different construction of gender and sexuality in this regard).
The fact is, cultures have very different ways of navigating the vast spectrum of human sexuality. I think there is a certain arrogance in assuming we have a better understanding of such matters than the ancient Greeks, for example, did. The assumption that our approach to understanding human sexuality is the only objectively correct approach is wrong, and that's a big part of the problem.