Not all criteria are constitutional. That's why you can't say people can only marry within their own race. After all, although black and white people could not marry each other, they can still both marry within their respective races, so equality, right? Nope. Wrong.
No words are being perverted. Marriage means many different things across cultures. That marriage includes unions of same-sex couples is a settled fact. A huge number of people consider marriage to include the union of two people of the same-sex. That is what the word means. Your religion might disagree, but your religion doesn't define civil law, nor does it own a monopoly on the word marriage. Period.
With Loving, the issue was about discriminations based on race. This is about a fundamental change to the institution of marriage itself, to make an exception for homosexuals. The problem is, a huge number of people also believe marriage is between a man and woman, and anything else is a contradiction of their religion which they cannot condone or support. The only "settled fact" is, there are two sides to this argument.
Now... Religion DOES define civil law, in fact, you'd be hard pressed to find any law that I can't directly tie to some religious belief to some degree. Nothing in the Constitution says our laws that we all decide on, can't be formed on the basis of our religious beliefs. In fact, we are protected from being discriminated against in any way, shape or form, because of our religious views. They certainly can be (and are) used as a basis for determining our laws.
Now, I am personally not religious, and I have a multitude of gay friends. My proposed solution to this issue comes from a gay couple who have been together 30 years, and who also oppose Gay Marriage. (Did I mention they had a Gay Wedding in rural Alabama in 1986?) So why would this couple be so opposed to "Gay Marriage" and the movement it has become? Aren't you curious?
The moral controversy is never going away, even if it becomes socially accepted. A very large contingent of people will always and forever believe that homosexual behavior is wrong and immoral. This is not like racism where prejudice was rooted in ignorance and bigotry, it is a foundational religious belief for most. So... even IF pie-in-the-sky social reform liberals get their way, and establish Gay Rights or whatever... it is going to be decades and decades before the society is going to embrace what is done. It's going to be a huge fight, the evangelicals don't play.
So the stage is set, the lawyers are going to make a fortune, and the everyday struggles of actual gay couples will continue as the battles rage on for... 10... 20... 30 years. Doesn't have to be that way.
This is a fundamental states-rights issue because it is the state who issues marriage licenses. The Federal role can only be to oversee this process to ensure fairness and equality, and that is where this whole movement is directed and aimed at, having the Fed tell the states what is acceptable. The ultimate danger in this is, what happens if there is a conservative sweep of power and the evangelicals simply have government 'undo' all the heathen marriage? Why give the government power over your choices and your life?
At the Federal level, you adopt a very simple directive to change the term "marriage" and all other subsequent terms like "spouse" or "couple" to a non-inflected term for the civil partnership. This kind of should be done anyway, now that we actually have several states with gay married partners. But what this does is takes the government, at the Federal level, out of the game. They are no longer the arbiters of what is marriage, how we define marriage as individuals. As far as taxes and benefits from the Federal government, they would only recognize contracts of civil union, and we would simply 'grandfather in' the existing marriage licenses out there. From here, you open the door for states to follow the lead and adopt civil union contracts to replace marriage licenses.
Suddenly, the problem is solved. No war, no 30 year crusade... it's done. Government isn't controlling your life, no one is telling you how to live, gay couples have all the benefits and perks, religious people still break the champagne glass and yell Mazal Tov! Traditional marriages still happen. Gay marriages start happening more.