[Question] What do the baby eaters tell us about ethics?

I just finished the baby eater sequence ( https://​www.lesswrong.com/​posts/​HawFh7RvDM4RyoJ2d/​three-worlds-collide-0-8 ) and aside from it being an incredibly engaging story I feel like there is a deeper message about ethical systems I don’t fully understand yet.

In the sequence introduction Eliezer says it makes points about “naturalistic metaethics” but I wonder what points are these specifically, since after reading the SEP page on moral naturalism https://​​plato.stanford.edu/​​entries/​​naturalism-moral/​​ I can’t really figure out what the mind-independent moral facts are in the story.

Another thought I’ve had since I read the story is that it seems like a lot of human-human interactions are really human-babyeater interactions. If you’re religious and talking to an atheist about God, both of you will look like baby eaters to the other. Likewise if you watch Fox News everyone on CNN or MSNBC will look like baby eaters but the same is true in reverse, everyone watching CNN will think Fox News are the baby eaters.

I have to say, this feels like some kind of ethical nihilism, but I would be curious to know if there are any canonical meta-ethical or ethical theories that correspond to the _message_ of the baby eater sequence, because if there is one, I think I agree with it.