In particular, one way (the way?) his metaethics might spit up something that looks a lot like moral realism is if there is strong convergence of values upon (human-ish?) agents receiving better information, time enough to work out contradictions in their values, etc. But the "strong convergence of values" thesis hasn't really been argued, so I remain unclear as to why Eliezer finds it plausible.
I don't think you're "confused" about what was meant. I think you understood exactly what was meant, and have identified a real (and, I believe, acknowledged?) problem with the moral realist definition of Good.
The assumption is that "if we knew more, thought faster, were more the people we wished we were, had grown up farther together” then a very large number of humans would converge onto moral agreement.
The assumption is that if you take a culture that practiced, say, human torture and sacrifice, into our economy, and give them the resources to live at a level of luxury similar to what we experience today and all of our knowledge, they would grow more intelligent, more globally aware, and their morality would slowly shift to become more like ours even in the absence of outside pressure. Our morality, however, would not shift to become more like theirs. It seems like an empirical question.
Alternatively, we could bite the bullet and just say that some humans simply end up with alien values that are not "good",
I don't think you're "confused" about what was meant. I think you understood exactly what was meant, and have identified a real (and, I believe, acknowledged?) problem with the moral realist definition of Good.
The assumption is that "if we knew more, thought faster, were more the people we wished we were, had grown up farther together” then a very large number of humans would converge onto moral agreement.
It's not the assumption that is good or bad, but the quality of argument provided for it.
There seems to be a widespread impression that the metaethics sequence was not very successful as an explanation of Eliezer Yudkowsky's views. It even says so on the wiki. And frankly, I'm puzzled by this... hence the "apparently" in this post's title. When I read the metaethics sequence, it seemed to make perfect sense to me. I can think of a couple things that may have made me different from the average OB/LW reader in this regard: