An economics editor should really know better. First, once you have the biological labels in your hand, the models are very like economic models. So he ought to be able to grasp them at least in outline. Second, in errecting absurd requirements for 'proof'.
This guy, and many of the other sceptics, often write as though the models have been improvised at high speed and for fun. But when you look into it it's an old literature with 1000s of papers, in its modern form going back to about 1930.
This is a new epidemic, and the key things the epidemiologists need to now to figure out the optimal distancing measures, and how many of us will die with and without them, are clouded in inevitable uncertainty [infectiousness, mortality rate, propensity to contact]...
But the experts know this! Research groups are debating it in real time, with the cloud of uncertainty budging this way and that as new studies are published. Their hive mind has experience fitting many past epidemics in our species and others.
You are not ever going to get 'proof' that the lockdown measures are needed. Certainly you won't get it from cross country studies [not sure if this is the ec ed being silly or devious mentioning that].
There are too many things varying across countries to isolate the contribution of differences in lockdown. You are not going to find naturally exogenous variation easily. This will be a great new literature, but I forecast that it won't ever 'prove' anything.
