We're all egalitarians, yes? We see the existence of racial or sexual or economic hierchies and we get sad brainwaves; we see people resisting them and we get happy brainwaves. I know Carrol has said he believes in freedom, not equality, which is of course a claim you most often see made by liberals of various stripes to mean exactly the opposite of what Carrol does - but without granting semantic sovereignty to either party, I think we know, in the broad strokes, everybody means by that. People have diferent values, or to put it less moralistically, desire incompatible things; hence, politics.
The standard left-liberal critique that social conservatives' opposition to homosexuality amounts to nothing more than "ew, gays!" is simultaneously correct and almost exactly wrong. *Of course* approbation of homosexuality is no more advanced than "ew, gays!," with of course interactions there that state sanction of same-sex marriage makes state-sanctioned marriage an alliance of equals, which hits to the real economic institution of the patriarchal family. They hate homosexuals and will sacrifice other goods to accomplish the denial of their rights. To say they think homosexuality is wrong is just to restate the same thing. If you say, instead, that you think disapproval of homosexuality is wrong, you're not making any truth-claim that contradicts theirs. You're saying "I want people to have full rights regardless of their orientation, and if you disagree with me, I will direct feelings of anger, disappointment, disgust toward you, although perhaps only mild ones, depending on my tone of voice." This is anything but abstract contemplation; it is emotional and directly experienced.
Of course we must use instrumental reason to determine whether particular courses of action will actually accomplish our goals, whether "moral" in this sense or mundane. The "should" in "should I have pasta, fish, or kebab this evening?" doesn't express a different meaning than "should I campaign for Barack Obama, engage in domestic terrorism, or post to an email list?" It's just that people have more of an interest in each other's answers to the second kind of question.
The moral - perhaps I should say "the ethical" - is a sociological and psychological category, not a metaphysical one. But moral language refers to concepts we find it useful to refer to. To answer shag's question, I - depending on which definition of morality you prefer - either don't think it's meaningful to talk about a political discourse that isn't expressed in moral terms or that no, there's no reason to use moral discourse. You can strip out the words right, wrong, criminal, whatever and still express the same concepts. It's just a particular kind of vocabulary that has a few culural markers, the same way that "I prayed all night, and God told me I should marry John" is a particular way of saying "I agonized over the issue and decided to marry John."