In particular, something that seems to me like a major failing is that I’m now 4 posts into a series on nutrition and I don’t know the right answer.

There seems to be pretty strong reason to think the right answer is "we don't know the right answer yet."

Actionability aside, not stating a view on what someone ought to conclude makes it hard to see just how wrong Taubes is or isn’t.

If you check out Guyenet's post (linked here, ChrisHallquist has linked it twice), he leads off with (paraphrased) "carb-free diets have worked for a lot of people, and that's great, but Taubes is wrong about the carbohydrate-insulin-hypothesis."

This article series began because the heuristic of "trust the expert consensus" was called into question, and Taubes came up as an opponent of the nutritional consensus, but it turns out that Taubes is mischaracterizing the expert consensus, even if he's not mischaracterizing the layman consensus (which, as you'd expect for laymen, is pretty bad). So that Taubes gets the expert consensus wrong is relevant to the meta-point of "trust the expert consensus."