Moral truth and the God of the gaps argument.

I think that the reality is simply that people who reject the idea of moral truth are simply repurposing the "God of the gaps" argument. They seem to rely on the fact that there are things that still mystify us about morality to show that it's time to throw the baby out with the bathwater.

No, that's not how this works.

The fact that a lot of people, including me, operate off of systems of moral values that we view as objectively true and that different systems are incompatible with others doesn't negate morality as a discipline of inquiry - something that we can learn more about and something that can either progress or regress.

The difference is an extra layer of absurdity. The people who make the God of the gaps argument believe in something that could possibly be true. The people who believe that there's no such thing as moral truth believe in something that is logically absurd from the get-go.