Update: When I wrote this I failed to properly take into account the legal ramifications of marriage. I will reconsider this and post my conclusions as part II.
I was doing my daily reading of The Volokh Conspiracy and came across the following in response to an an article by Andrew Sullivan (emphasis added):
Whether one approves of homosexuality or not (I see nothing wrong with it, but I know others disagree), it's a real phenomenon that isn't going to go away. There are gays and lesbians out there; there were even when homosexuality was subject to very serious social and legal penalties; they're not going away. The question is: What do we do about them? Do we encourage them to form stable unions, or not? If they are in our families, do we fully accept them, or allow this to alienate them from us? Even someone who thinks homosexuality is against God's plan should, I think, ask what is the most helpful and loving way to deal with this reality; and neither criminalization, nor ostracism, nor, I suspect, denial of the ability to marry is likely to be the right answer.-Eugene Volokh
This is a confusion that is surprisingly common and hinges on the question of what marriage is. At its most basic, marriage is a a set of reciprocal promises -- a contract. As such, it is made between two people and the rest of the community has nothing to do with it. Two people can make marriage vows if they are the only human beings on earth. The main job of the priest during this part of the ceremony is to tell people their lines in a round-about fashion. Indeed, the traditional thing which the priest (or other officiator) says immediately following the exchange of vows is most telling: "I now pronounce you man and wife." Let's just grab our dictionary and look up pronounce, shall we?
Pronounce Pro*nounce", v. i.
1913 Webster
1. To give a pronunciation; to articulate; as, to pronounce
faultlessly. --Earle.
1913 Webster
2. To make declaration; to utter on opinion; to speak with
confidence. R. --Dr. H. More.
1913 Webster
The second definition is what we're after: To make a declaration; to utter an opinion; to speak with confidence. The priest does not marry the couple, they marry themselves. The priest merely declares when it is done. Indeed, the priest largely stands in for the community in its only important role in the marriage service: to witness the vows. The witnessing serves both for the practical use of having witnesses and also as a form of approval. If the community did not want two people to marry, they would not show up; they would not give formal recognition that the two have married each other.
Now we come back to Professor Volokh's "denial of the ability to marry". So far as I know, no one has proposed laws banning the reciprocal making of promises to love, honor, cherish, etc. between two men or two women. So far as I know, there are no promises which it is illegal to make and the worst that the government can do is refuse to enforce promises which it doesn't like (for example, contracts to illegal activities are simply not enforceable). If this is not correct and there exists legislation which prohibits gay couples from promising to always love each other (etc.), then it should be repealed straight away. What people promise to do is not the business of the state (at least as long as the promised action is not illegal).
However, refusal to approve of something is by no means the same thing as to prohibit it. Professor Volokh himself said as much when he discussed Lynne Stewart. Stanford's refusal to honor her in no way restricted her freedom of speech. Similarly, if the community at large does not approve of gay marriage, it does not prohibit gay marriage by doing so.
There are good arguments for both sides of gay marriage. There are good arguments for both sides of the community approving of gay marriage (in the form of officially recognizing it). However, the benefits to gay people's psyche is a bad argument in favor of officially approving of gay marriage.
In the abstract, I'm sure that we all want everyone to be infinitely happy. However, there are rather severe practical limitations which reality imposes on this wish. One of them is that no matter how much someone wants us to believe something (approval is nothing but the belief that the thing being approved of is good given the circumstances), it is intellectually dishonest to believe it merely to make them happy. Some people would be much happier if the official policy of the government was that the book of genesis is literally true (except where it isn't) and that the earth is 6,000 years old. This is not a legitimate reason to officially believe it. Some people would be much happier if everyone thought that white people were all racists. That's not a legitimate reason to officially believe it. Some people would be happier if the United States had fell into the sea. That's not a legitimate reason to believe that it has, either for those of us in the US or those who aren't. Some people would be happier if the official policy of the government was that homosexual marriage is as legitimate as heterosexual marriage. I don't see why the importance of homosexuals is more important than the happiness of creationists, Al Sharpton, or the Germans.
Happiness is a good thing, but it does not trump honesty. A thing is true or it is not and all the happiness in the world that hinges on it will not make it true or false if it is otherwise. (This of course cuts both ways: if it is the case that homosexual marriage is good then it is the duty of all honest men to approve of it.) None of this is meant as a discussion of the complicated topic of whether or not homosexual marriage should be approved of. I merely point out that it is not the same question as whether or not homosexuals may marry each other and that it cannot be answered on the basis of what answer will make homosexuals happy.