I'm reminded of discussions I've had surrounding the coherence theory of truth, that truth with a capital T consists in the internal consistency of a set of propositions. One common argument against this is that you could have two systems that are equally coherent, but that disagree on some particular proposition. That seems to be a contradiction. The problem is that there is no "outside the systems" from which to compare the two -- you're simply creating a third combined system that isn't fully coherent. That's not an allowed operation as there is no "outside the system." Truth, in coherence theory, is a property that systems and propositions within systems have. There is no outside perspective. Suggesting an outside perspective is failing to grant the full set of premises of coherence theory and amounts to a bit of question begging.
Your complaint about the seeming anti-realism of relativism seems similar in that you're not granting the full tenets of relativism and instead are importing a concept of "real morals" which is foreign to relativism and can't meaningfully be compared. Morals in relativism are a construct of society and within that society they have a real existence.
I can't help but be reminded of your suggestions about morals being real if they provide fruitful explanations in Neo's thread. I have to wonder if you're willing to apply that to moral realism but not to moral relativism.
Anyway, just some initial thoughts.
Your complaint about the seeming anti-realism of relativism seems similar in that you're not granting the full tenets of relativism and instead are importing a concept of "real morals" which is foreign to relativism and can't meaningfully be compared. Morals in relativism are a construct of society and within that society they have a real existence.
I can't help but be reminded of your suggestions about morals being real if they provide fruitful explanations in Neo's thread. I have to wonder if you're willing to apply that to moral realism but not to moral relativism.
Anyway, just some initial thoughts.