There's every reason to codify "liver yin deficiency pattern." If you've got "liver yin deficiency pattern" statistics on a billion Chinese citizens, and you can run comparative analysis to determine a Venn diagram of what western maladies (hypertension, high cholesterol, etc) fall under "liver yin deficiency pattern", you've just increased your sample size by a billion.
The John Snow argument is that he used nonconventional methods and approaches (remember, this is before germ theory) to lessen a cholera outbreak. Mass hysteria has nothing to do with it - this is a terminology and taxonomy discussion because ICD codes are used for terminology and taxonomy only. They are the lingua franca of medical afflictions. "Scientific?" "Unscientific?" You... do realize that by phrasing things like that you're arguing that a form of medicine practiced by one fifth of the population of the world is hogwash, right?
Now: you can think it's hogwash. I can think it's hogwash. We can all agree that it's hogwash but the fact of the matter is, if it's the hogwash in place, it's the hogwash you interact with. Full stop. Even now, you've got a religious fervor about your value system and you want to smite the infidel for believing something else... how you think that's gonna go over? Gonna crusade on in there and insist they believe in the god of hypertension?
As to your "titanic amount of work" you are arguing - in this very thread - that the whole of the effort is not undermined by some silly shit. Yet here you are, panties in a twist over the silly shit. Which is it? Which is it going to be? Does all of the terminology matter? How much silly shit is okay? Oh, but it's the principle of the thing, right? I mean, "hit by a meteor" is a factual problem while "liver yin" is not.
but that's because you didn't grow up with liver yin. Neither did I. But I'm not arrogant enough to argue that everyone has to accept my terminology, especially when we're talking about bringing it under the umbrella of conventional medicine where it has to peacefully coexist with shit in the Lancet.
Now go ahead and explain how bringing up "mass hysteria" is anything other than an argumentative, insulting and counterproductive tangent to inject into this conversation. I'll wait.