Having had something of an unpleasant run-in with a trio of genocidal asshats recently, I thought that I would set down my thoughts regarding an interpretation of the Old Testament law.
The first point to be made is that as an anthropological relic, it's not particularly objectionable--certainly no more so than Egyptian or Assyrian practices from the same approximate region and historical epoch.
What gets people's goat about the OT law is not its actual content but the claims made about it. First, that it proceeded as-is from the mind of an all-knowing and all-loving God, and second that it should be consulted when formulating policy in a technological democracy.
Stripped of the extenuating anthropological context and ascribed to a transcendent Divine, the idea that a rape victim should be executed for not screaming is not only abhorrent, but utterly inexcusable. In the socio-religious climate of the ancient near-east, one can understand, to a degree, the objection to profaning calendar numerology, but in a 21st century nation-state with overtime laws and part-time jobs, the death penalty for working on Saturday is inhuman and absurd.
The belief in a good God is tautologically incompatible with the doctrine of scriptural inerrancy. A being who gave such commands cannot--a priori--be referred to as good.
My personal explanation for the Levitical code is to view it as a human construct ascribed to Deity for good measure. Men have always used God to mask their own ambitions, and to bolster their own authority.
Now I'm aware that many will try to make an argument along the lines of 'Well, many of the forbidden foods in the OT carry the risk of infection if not cooked properly!" The obvious rejoinder is two-fold: 1) many of the ALLOWED foods do, too; and 2) If that was the point, then why didn't God just explain what germs were and tell them to cook their meat well? Even if we concede that there was some health benefit to following the dietary prescriptions, that would not evidence divine authorship so much as coincidence in food choices that were made for ceremonial reasons or else simple observation on the part of the human authors.
So for someone like me, who rejects divine dictation/inscription, Levitical injunctions regarding modern behavior are irrelevant at best. And no, that doesn't mean that I feel free to go around killing people and committing adultery willy-nilly. I know that these behaviors are destructive and immoral quite apart from the pronouncements of the desert nomads who slaughtered their way into Palestine three thousand years or so ago. Our word for people who do not is psychopath*.
But suppose that you believe that the law in some measure comes from God--what then? Is it really possible to ignore certain verses regarding, say, homosexuality?
The simple truth is that you already do. Leviticus 20:13 says that a) homosexual dalliance is an abomination and b) those who practice it should be killed. Accepting B means advocating genocide--there are millions if not hundreds of millions of men in the world who have had sexual contact with other men. I presume that you do not think that they must be all killed, but in failing to think so you contradict one whole half of the verse.
If we reject one half of the verse, why mayn't we reject the other half, as well?
Even if you take the interpretation that God dictated the law as such, and even if you groundlessly assume that He meant it for other people than the Jews, then there are still two insurmountable facts to deal with. First that Christ fulfilled the law, and, according to Paul, set us free from it. And second, there's the fact that you aren't following the law.
No, really--you aren't following the law. Mildew. Diet. Fabric. Agriculture. Rules for determining guilt in adultery. Refunds for non-virgin brides. Property redistribution and debt cancellation. You really, really aren't following the law.
In light of that, I pose a question: Jesus had some famously harsh words for the Pharisees who kept the letter of the law while laying its heavy burden upon others. How much more harshly will He judge those who lay a heavy burden on others while ignoring the letter completely?
*The common implication that finding the law abhorrent on certain points somehow obligates me to disagree with it on every point is really quite silly. The fact that I prefer Lysol to scarlet yarn and hyssop does not obligate me to think murder acceptable. Likewise the fact that the law speaks against murder does not obligate me to accept its remedies for mildew, or anything else.