I'm afraid that I am still not being understood. Firstly, the concepts of universalism and moral realism still make sense even if agent preferences have absolutely no impact on morality. Secondly, the notion that 'moral formalisms' can be true or false makes me squirm with incomprehension. Third, the notion that true formalisms get weighted in some way by agents leads me to think that you fail to understand the terms "true" and "false".
Let me try a different example. Someone who claims that correct moral precepts derive their justification from the Koran is probably a moral realist. He is not a universalist though, if he says that Allah assigns different duties and obligations to men and women - to believers and non-believers.
In You Provably Can't Trust Yourself, Eliezer tried to figured out why his audience didn't understand his meta-ethics sequence even after they had followed him through philosophy of language and quantum physics. Meta-ethics is my specialty, and I can't figure out what Eliezer's meta-ethical position is. And at least at this point, professionals like Robin Hanson and Toby Ord couldn't figure it out, either.
Part of the problem is that because Eliezer has gotten little value from professional philosophy, he writes about morality in a highly idiosyncratic way, using terms that would require reading hundreds of posts to understand. I might understand Eliezer's meta-ethics better if he would just cough up his positions on standard meta-ethical debates like cognitivism, motivation, the sources of normativity, moral epistemology, and so on. Nick Beckstead recently told me he thinks Eliezer's meta-ethical views are similar to those of Michael Smith, but I'm not seeing it.
If you think you can help me (and others) understand Eliezer's meta-ethical theory, please leave a comment!
Update: This comment by Richard Chappell made sense of Eliezer's meta-ethics for me.