Murder is certainly not wrong_x for every agent x - we can think of an agent with a preference for people being murdered, even itself. However, it is almost always wrong_MattSimpson and (hopefully!) almost always wrong_lukeproq. So it depends on which question your are asking. If you're asking "is murder wrong_human for every agent?" Eliezer would say yes. If you're asking "is murder wrong_x for every agent x?" Eliezer would say no.
(I realize it was clear to both you and me which of the two you were asking, but for the benefit of confused readers, I made sure everything was clear)
I would be very surprised if EY gave those answers to those questions.
It seems pretty fundamental to his view of morality that asking about "wrong_human" and "wrong_x" is an important mis-step.
Maybe murder isn't always wrong, but it certainly doesn't depend (on EY's view, as I understand it) on the existence of an agent with a preference for people being murdered (or the absence of such an agent).
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.