I am not saying that it is entirely subjective. Still I don't know what would you or the author of the post accept as valid explanation in this very case.

something that is as explanatory as other explanations. I don't think it is a case of raising the bar artificialy high

The assertion that certain wavelengths are perceived as green are sufficient explanation of the concept of "green" in terms of physics of elementary particles.

I don't think any special pleading is needed to reject that as an explanation. It doens't even look like an explanation--it contains no "because" clauses. Explanations do not generally look like blunt assertions, and and, as I noted before, allowing blunt assertions to be explanations leads to a free-for-all.

It is contentious whether to call the historian's work as description of the causes or explanation thereof. Anyway, I don't wish to get into a debate over the meaning of "explanation".

I don't see why not. It seems to be a key issue.

I just wanted to point out that Mitchell_Porter appeared to be (at least when he was writing the post) quite certain that no detailed account of the correspondence between physics and neural activity could faithfully capture the concepts of colours, whether the account included causal relationships or not.

Yes. A lot of people have that intuition.