Easily, less than five percent of the U.S. population is homosexual. So, why is it that being pro-homosexual is advantageous for one seeking public office? I think the answer is simple. The average person is autonomous in his reasoning and is, therefore, easy prey.
Although all men know by nature that homosexuality is sin, it’s only through Scripture that one can prove in any robust, epistemic sense that it is sin. (All over this site I draw the distinction between knowledge and the justification of knowledge.) Since most Americans are autonomous in their reasoning, then it stands to reason that most Americans are incapable of justifying any moral claim they even know to be true. Recognizing that something is abnormal, even unnatural, doesn’t make it immoral, let alone something that should be deemed illegal. And if not illegal, then worthy of government protection.
Although many straight people still find homosexuality unnatural - unnatural does not imply moral deviance. God’s general revelation of sin has grown dim in the minds of most Americans, but even when it was shining more brightly, it was never to be interpreted apart from special revelation, God’s word. With the rejection of the Bible, Americans are left to grope in the dark. Christians can rejoice in at least this: God is not mocked!
Apart from invoking Scripture one is left with two unhappy alternatives. Rather than appear arbitrary and hateful toward someone who is merely different than us, the "open minded" (to everything but God's word!) are left to defend deviant behavior even when “it’s not my cup a tea.” The more noble must even fight for it! Apart from a commitment to Scripture, the only way to avoid arbitrariness and bigoted rejection of such a perversion (that comes to us under the guise of "love" and "equality" no less) is to accept it - even defend it. Apart from Scripture one is left either approving, at least tacitly, ungodly behavior or else undergoing the self-inflicted guilt of arbitrary hatred toward a practice one simply doesn't prefer. Righteous disapproval is not available to us apart from values informed by Scripture. The fool (one who rejects God's word) is confounded once again.
It takes God’s word to justify the premise that homosexuality is sin, absolutely. Yet even among those who see this plainly in God’s word, it’s only a minority who see that the practice of homosexuality should be deemed illegal.