Same-sex marriage is, for its opponents, a social issue that shouldn't be decided by courts but rather through the democratic process. To do otherwise would perpetuate the idea that the heroes in these change events are judges and lawyers.
Legalizing same-sex marriage and Marijuana should quiet down those homophobic readers of Leviticus 20:13: "If a man lies with another man he should be stoned."
Same-sex marriage is not in the government's direct interest since one of the functions of marriage is for the state to incentivize couples to stay together and create a stable family unit in the event of an accidental, unintended/unplanned pregnancy.
Same-sex marriage is not in the government's interest because it discourages heterosexual couples from marriage.

Same-sex marriage is not a matter for the courts, on the grounds that fundamental social change is better cultivated through the democratic process.

Same-sex marriage is not constitutionally protected, nor a matter for the courts because although the 1967 supreme court ruling in loving v. Virginia, which legalized interracial marriage, ruled that marriage is indeed a 'fundamental right' this 'right' does not apply to same-sex couples because sexual orientation has not been viewed by the supreme court as a protected class.
Same-sex marriage is a recognition that relationships are about more than gender. After all, Valentine's Day cards generally do not read 'my favorite thing about you is that you're the opposite sex.'
Same-sex marriage is the demand for an equality that amounts to a requirement of action (i.e. Making a person do something, such as forcing ministers to preside over weddings they don't approve of), which is unpalatable to many of our citizens for religious reasons.
Same-sex marriage is not constitutionally protected nor a matter for the courts because it is not an inherent right specifically protected by the constitution.