Why does it appear to make sense to wonder if we are valuing the right things, when Good is just whatever we value?
We are in the habit of (and reinforced for) asking certain questions about actual real-world things. "Is the food I'm eating good food?" "Is the wood I'm building my house out of good wood?" "Is the exercise program I'm starting a good exercise program?" Etc. In each case, we have some notion of what we mean by the question that grounds out in some notion of our values... that is, in what we want food, housing materials, and exercise programs to achieve.
We continue to apply that habitual formula even in cases where we're not very clear what those values are, what we want those things to achieve. "Is democracy a good political system?" is a compelling-sounding question even for people who lack a clear understanding of what their political values are; "Is Christianity a good religion?" feels like a meaningful question to many people who don't have a clear notion of what they want a religion to achieve.
That we continue to apply the same formula to get the question "Are the values I'm using good values?" should not surprise us; I would expect us to ask it and for it to feel meaningful whether it actually makes sense or not.
You can argue that the things your theory can't explain are non-issues. I don't have to buy that,
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: