Jonathan Haidt and others have fairly convincingly documented that humans have a moral intuition which, while somewhat trainable, seems to have a lot of commonalities across cultures. So Nebulasaurus can't be entirely correct: not only do the moral tastes seem to be common across basically everyone (though how much we taste each flavor varies), it's quite likely that it's there for some adaptive purpose (Haidt speculates on the purposes in The Righteous Mind).

However, Haidt (and others) have also fairly convincingly documented that most moral judgments are intuition-first, rationalization-later. Because the intuitions aren't perfectly shared, just approximately, and we're kinda mostly not actually thinking about the rational justifications, Bonigo Montoya seems to be simultaneously overselling and underselling the universality of morality by pinning it on "us". Overselling because our intuitions don't fully agree and if it really does all come down to "what we sing in harmony" we end up needing morality, which we don't agree on, to decide on the harmony. Underselling because in not identifying any way to couple "isness" to morality, the aspiration to universality is ungrounded.

If we return to the idea that our morality isn't here by accident, then we can identify a type of "harmony with what is" that probably isn't very much like what either C. S. Lewis or Bonigo Montoya had in mind, but is that morality is useful for fitness taking everything fully into account. None of the silly "I had more kids" stuff--did the kids have kids, and did they, and aren't we all closely related enough for it not to actually matter all that much, and waitaminute did thermonuclear war cut it all short somewhere? Evolution acts locally from generation to generation, but it is only through all time that the overall success is determined.

I would hesitate somewhat to call this realization morality because in sufficiently weird circumstances--the kinds that philosophers love to come up with--it might clash rather violently with many people's moral intuitions. Do we call the readout of these intuitions, sculpted by culture and consideration of consequences, "morality"? In practice, it seems yes. But if your morality causes the extinction of the species, something has gone seriously, seriously wrong. And, you know, I didn't mention thermonuclear war for no reason. We possibly could get it that wrong.

The universe wouldn't care, because universes don't care about things. But if we were the type of creature who set aside our instincts when we recognized that the instincts were only ever there to guide our survival and now they're pulling the wrong way--much like we set aside our desire for sweets if we have diabetes--then our survival prospects would be greatly increased. In the very long run, only those sorts of creatures are likely to persist: only creatures who can wield whatever intuitive morality they have in the service of continued existence whenever the stakes are so high that this is an important concern.

I rather hope that we can be that kind of creature.