The problem with the standard jargon is that "realism" is used to label a metaphysical and an epistemological claim. I like to call the epistemological claim, that there is a single set of moral truths, moral objectivism, which clearly is the opposite of moral subjectivism.
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: