Without commenting on whether this presentation matches the original metaethics sequence (with which I disagree), this summary argument seems both unsupported and unfalsifiable.
Would this be an accurate summary of what you think is the meta-ethics sequence? I feel that you captured the important bits but I also feel that we disagree on some aspects:
V(Elves, ) = Christmas spirity
V(Pebblesorters, ) = primality
V(Humans, _ ) = morality
If V(Humans, Alice) =/= V(Humans, ) that doesn't make morality subjective, it is rather i...
Unpacking "should" as " morally obligated to" is potentially helpful, so inasmuch as you can give separate accounts of "moral" and "obligatory".
The elves are not moral. Not just because I, and humans like me happen to disagree with them, no, certainly not. The elves aren’t even trying to be moral. They don’t even claim to be moral. They don’t care about morality. They care about “The Christmas Spirit,” which is about eggnog and stuff
That doesn't generalise to the point that non humans have no morality. You have m...
Morality binds and blinds. People derive moral claims from emotional and intuitive notions. It can feel good and moral to do amoral things. Objective morality has to be tied to evidence what really is human wellbeing; not to moral intuitions that are adaptions to the benefit of ones ingroup; or post hoc thought experiments about knowledge.
Clarification please. How do you avoid this supposed vacuity applying to basically all definitions? Taking a quick definition from a Google Search: A: "I define a cat as a small domesticated carnivorous mammal with soft fur, a short snout, and retractile claws." B: "Yes, but is that a cat?"
Which could eventually lead back to A saying that:
A: "Yes you've said all these things, but it basically comes back to the claim a cat is a cat."
Definitions are at best a record of usage. Usage can be broadened to include social practices such as reward and punishment. And the jails are full of people who commit theft (selfishness) , rape (ditto), etc. And the medals and plaudits go to the brave (altruism), the generous (ditto), etc.