You're referring to the ruling from anti-misegnation laws which criminalized interracial marriages but did not render them not recognized as actual marriages.
For one thing, the case you’re referring to, Loving v. Virginia, deals with a statutory scheme that did both: it criminally punished miscegenation and, under section 20-57 of the Virginia Code, voided all interracial marriages. Voiding interracial marriages carried out in another state (like the plaintiffs in that case) seems to me to be a violation of the Full Faith and Credit Clause, but apparently that never really materialized, so whatever.
More importantly, you’re making an irrelevant distinction. It really doesn’t matter whether a state refuses to recognize gay (or interracial) marriage, or whether they criminally punish it while still recognizing it, or both. All three are certainly infringements on the right to marry. Loving isn’t limited to criminal punishment of interracial marriages.
Finally, I’m aware that the Court has never actually held that marriage is a fundamental right; the language in Loving saying as much is dicta. The reason I’m so bluntly stating “marriage is a fundamental right” is because I find it very hard to believe that the Court, having literally stated that marriage is a fundamental right (dicta or not), as well as generally waxing lyrical about how awesome and important marriage is on numerous occasions, could seriously make the argument that, oh wait, marriage isn’t a fundamental right for Due Process Clause purposes, sorry if you misunderstood us before.
In a very technical sense they already are. They are permitted to marry any consenting adult who is not an immediate family member or already married.
Uh, what? No they’re not. That’s kind of the point. I have to assume you meant “any consenting adult of the opposite gender.”
I’ve seen that argument before, and it’s mind-boggling to me how anyone can say with a straight face that homosexuals already have the right to get married. Yes, in the most technical, literalistic, and heartless sense imaginable, homosexuals have the same “right to marry someone” that heterosexuals do. But that is not equal treatment. No one who lives in the world could possibly say that homosexuals and heterosexuals enjoy the same marriage rights under that interpretation. A right to marriage, but not to the gender you’re romantically and sexually attracted to, is no right at all.
Besides, this argument only works in the Due Process Clause context, and basically what it amounts to is saying “the fundamental right to marriage isn’t being violated by state bans on gay marriage, because the right to marriage is a right to marry a consenting adult of the opposite gender, which homosexuals can already do.” Leaving aside how, as I said, that’s an intuitively silly argument, it’s begging the question by defining marriage as a threshold matter. The first question to be argued before the Court is whether the Fourteenth Amendment requires states to license marriage between people of the same sex, and part of that is determining the contours of the right to marriage. Consequently, it would be improper to assume that, by definition, this right only extends to individuals of opposite genders.
Maybe even more fundamentally, the question (in my opinion) is not “is there a fundamental right to same-sex marriage protected by substantive due process?” The answer to that is obviously no. Same-sex marriage is certainly not “deeply rooted” in the nation’s history and tradition, and probably not “implicit in the concept of ordered liberty.” But there wasn’t a “fundamental right to interracial marriage” either. Nor would it have been proper in Lawrence v. Texas to define the question as “is there a fundamental right to sodomy” rather than “is there a fundamental right to ‘personal decisions relating to marriage, procreation, contraception, family relationships, child rearing, and education’ which sexual acts, including sodomy, might fall under.” This is a relatively new legal issue: you can’t just slap on a qualifier, narrowing the scope of the discussion, and then act shocked when you don’t find a specific “right to [specific qualifier] [general right]” in the nation’s history and tradition. Particularly since the whole reason such discussions arise is because they’re not deeply rooted in the nation’s history and tradition, and people are seeking recognition for them now. Instead, you look for the general right, and then you ask if the specific interpretation of it being considered is justified.
In short, the proper question is “is there a fundamental right to marriage,” to which the answer is almost certainly yes, and then “can that right constitutionally be denied to homosexuals?” To which the answer must be no.
And…
What they want is the current definition of marriage to be expanded, which is wanting something new. There's nothing wrong with arguing that, but it's dishonest to frame it the way you are. The argument is essentially redefining marriage to argue marriage should be redefined.
…for one thing, I’d say that while marriage has historically been treated as being exclusively between a man and a woman, that doesn’t mean that marriage is defined as being between a man and a woman. But more importantly, and more in keeping with what I said above, this is why I don’t feel that I’m arguing for marriage to be redefined, or framing the question improperly. I’m not assuming that marriage, by definition, is between two consenting adults of any gender; I’m simply not (dishonestly and improperly) adopting a definition of marriage that forecloses that conclusion before I’ve even begun. What I’m doing is assuming that marriage is a bond between two people, and the question is whether it can apply to two consenting adults of any gender (or not). I reserve judgment on whether gender is irrelevant, or whether it’s inherently between opposite genders, while considering the arguments for both sides; and as a consequence of that analysis, I find it impossible to avoid the conclusion that gender is irrelevant.
Now I'm not against gay marriage
Then why bother making these arguments?
So basically it's: "society decides what laws we have and that venerates them, except when I don't like them, then exceptions should be made, and those exceptions don't apply when society doesn't think it should". It's complete special pleading and hypocrisy.
No, it’s “the world doesn’t necessarily operate on principles of rigid logic, and even if such principles dictated that if gay marriage is to be legal then incestuous and polygamous marriages have to be too, which they don’t, nobody actually wants incestuous and polygamous marriages, so as a practical matter they’re not going to happen.”