The problem isn't spreading memes in and of itself. "Flatten the curve" is the same kind of statement as "we stay here for you, you stay home for us" or "we will defeat this invisible enemy"; it's a motivational poster, a compact way for people to remind themselves what's happening and why their efforts are important. The problem is when people start trying to interpret the memes as *policies*, and argue about whether the curve can indeed be flattened or declare that we'll be in lockdown for N months because otherwise the curve won't be flat.
Are you accounting for efforts to increase critical care capacity? Most Western governments seem to be acknowledging that cases will blow up, and the only question is whether we can get enough ventilators in time for the peak.
The excess deaths in the model are caused by a red line of critical care capacity, which the study assumes is fixed at 14 per 100,000 population in the US. If the curve of cases requiring critical care rises too high, 100% of cases above the red line will die even though 50% could have been saved.
But the coronavirus doesn't need the entire package of critical care a hospital might provide, just a ventilator and a bed. So the US is aiming to simply build enough ventilators to hike the red line above the curve. (I would assume the UK is doing the same thing but I haven't been following their response.)
Ground glass opacity is named after its visual appearance on a CT scan. Information I can find (and I'm not a doctor, don't trust me at face value!) suggests that it's generally reversible and doesn't indicate any more severity than the pneumonia it's detecting.
The obvious question to reconcile the Diamond Princess and Veneto is: do the tests have subclinical thresholds, and if so are they different? I don't know where to begin researching that, though. (And as a more general concern, I worry the entire line of questioning might be overfitting, maybe there's some random reason that has nothing to do with the general pandemic.)
The money quote is misleading, because they don't actually have a mechanistic model. They're just fitting a parameterized logistic curve to all the death data in the world. They incorporate some black-box factor that causes more deaths without social distancing, and arbitrarily declare that factor's effect is 66%/33%/0 with 1/2/3+ social distancing measures. The goal isn't to claim that nobody's ever infected in the 0 case, just that the not-social-distancing factor is gone, so our course should follow the empirical progression of countries that do social distancing.