Well, it works OK if you give up on the idea that "right" has some other meaning, which he spent rather a long time in that sequence trying to convince people to give up on. So perhaps that's the piece that failed to work.

I mean, once you get rid of that idea, then saying that "right" means the values we all happen to have (positing that there actually is some set of values X such that we all have X) is rather a lot like saying a meter is the distance light travels in 1 ⁄ 299,792,458 of a second... it's arbitrary, sure, but it's not unreasonable.

Personally, I would approach it from the other direction. "Maybe X is right, maybe it isn't, maybe both, maybe neither. What does it matter? How would you ever tell? What is added to the discussion by talking about it? X is what we value; it would be absurd to optimize for anything else. We evaluate in terms of what we care about because we care about it; to talk about it being "right" or "not right," insofar as those words don't mean "what we value" and "what we don't value", adds nothing to the discussion."

But saying that requires me to embrace a certain kind of pragmatism that is, er, socially problematic to be seen embracing.