Assuming that your audience isn't familiar with the sequences and proceeds to go read the article, yes, that's not succinct. But the audience probably already has a cached idea of disagreements being semantic conflicts, so while he's not literally in a position to get the same idea across in two words, it could probably be compressed down at least as far as

"When I say that I 'ought' to do something, I mean that it's in accordance with my own innate desires and values as a human. My values and desires are real 'is' facts about the universe with a physical basis, and so 'ought' facts can be neatly derived from 'is' facts. This is as useful a definition of 'ought' as you're likely to get, and a definition that divorces normative facts from positive ones, saying that you cannot derive an 'ought' from an 'is' doesn't offer any practical advantage."