Same-sex marriage does not threaten religion

Why can't religious people support the right to gay marriage without supporting gay marriage itself?

gay pride us supreme court 521 (photo credit: REUTERS)
gay pride us supreme court 521
(photo credit: REUTERS)
In 1967 the US Supreme Court issued a ruling in Loving v. Virginia that overturned a ban on interracial marriage and pronounced marriage a "basic civil right." Now, in United States v. Windsor, the Supreme Court delivered a landmark victory for same-sex couple rights by requiring the federal government to recognize same-sex marriage in states where it is legal. In 1967 it was interracial marriage equality. In 2013 it is same-sex marriage equality.
As an observant Jew and a heterosexual, married male, I see no conflict with supporting the legal right to gay marriage, even if I don't religiously support the union itself. According to the literal dictates of biblical law, atheism, homosexual intercourse, lobster, pork, and interfaith marriage between a gentile and a Jewish person are all forbidden, but I would not oppose a person's right to engage in any of those activities.
Supporting the right to do something does not mean one has to support the actual act. I, for instance, support the legalization of marijuana, but I do not support smoking marijuana. I support the First Amendment right of the KKK to demonstrate, but I still condemn their ideology. I support the right of adults to drink alcohol to their hearts' content (or to their livers' failure), but I do not support alcoholism. Is this hypocrisy? Of course not, because one should recognize that in a free society, believing in someone's right to do something does not mean you have to support what they are doing. The distinction is similar to recognizing the difference between personal beliefs and what should be public policy.
Why can't religious people support the right to gay marriage without supporting gay marriage itself? As an observant Jew myself, I support the rights of gays to marry and receive all rights attendant to marriage.
None of the religious organizations and politicians that single out gay marriage on biblical grounds would support a ban on interfaith marriage or the use of condoms, or lobby for legislation forbidding people to eat at Red Lobster, despite these activities being forbidden according to a strict interpretation of biblical law. Atheism is also as much against their religion as homosexuality is.
These organizations and politicians would not oppose the constitution's No Religious Test Clause, which states that "no religious test shall ever be required as a qualification to any office or public trust under the United States," despite the biblical prohibition against atheism. They should not oppose gay marriage, either, despite the arguable biblical prohibition against it.
Finally, for fellow observant Jews claiming that Sheva mitzvot B'nei Noach laws demand that Orthodox Jews impose a biblical view of marriage on society, it is noteworthy that many rishonim (leading rabbis who lived during the 11th to 15th centuries, approximately), including the Ravad, Nachmanides, and Tosafot, ruled that there is no obligation to impose Noachide laws on society.
At the end of the day, Jews and non-Jews should want to follow the dictates of their religion out of their own volition, not through coercive laws abridging people's right to marry.
Eliyahu Federman's writing has been published in The New York Times, The Jerusalem Post, The Forward, USA Today and elsewhere on issues related to sexual abuse awareness, gender equality and police-community relations. He graduated law school in NY, where he served as executive editor of law review.