If your position is that certain morals are inherent, that very well could be. I know some speculate a genetic moral tendency. I don't rule most anything out entirely.
I think the genetic argument will fail for the same reason as the 'opinion' argument. You still never get justice without an objective standard. Period.
What kind of legal system will we have when the following precedent is set? "My client is genetically predisposed to baby rape. This is just part of his evolution. What makes your genetics better than his genetics?" Eventually, justice just has to say, "You know what, baby rape is just wrong. Period."
I believe every person has a fairly common, but imperfect copy of an objective moral law imprinted on their heart, and we call it a conscience. Because it is imperfect, it must be informed by the Word of God, and transformed by the power of God. Many of these are self-evident, and we can appeal to this objective law.
Every time you argue with someone about what they "should" have done, you have appealed to this objective, common moral law. Every time you made an excuse for breaking it, you nodded to its existence. That's why I (unfortunately) have to personally question the validity of PKT's posts. He expresses the belief that morality is just a matter of multiple, equally valid opinions and he can not judge anyone on theirs.
But I bet we could mine the forum history of his posts and find him arguing with someone about what they "should" do. I'll bet he's called someone morally wrong in some form or fashion. I bet if we followed him around for a day or two, he would complain that someone mistreated him and shouldn't have. As soon as he's done that, he's appealed to a common, objective morality. That's when he finds it impossible to live out his worldview. He believes it maybe, but it goes against what he "really" knows to be true.
:hi: