Thanks IB. I agree with the entirety of your second paragraph. I've been advocating a South Korean model all along. There are a so many things we should be doing other than locking down. In their absence we do get what we've got now.
As for the paper it's not possible to draw conclusions about the lockdown severity if the other conditions differ so dramatically. I was being generous to them.
They acknowledge that other social measures might alter outcome but then focus almost exclusively on the severity of the lockdown.
When comparing a difference between two groups - light and heavy lockdown - they should try and evaluate what confounding factors might explain their findings. So whether they wrote it into the paper or not anyone reading it should understand that comparing the difference between france and korea is a comparison between hard lock down/inadequate test and trace and light lockdown/effective test and trace. The differences between the two groups might all be explained by the testing and isolation - the korean's were super effective - the french like us have been poor - and nothing to do with the severity of the lockdown. Without that analysis I'd say the conclusions are hard to support.
There also seems to be a significant selection bias.
How did they come to use only those 10 countries all of which have failed to control the virus other than they set up the conditions to get the result they wanted. Why not include New Zealand, Vietnam, China in the analysis?
If the authors really wanted to demonstrate the effects of lockdown sever and light why not compare sweden with norway and finland. Those countries seem much more closely matched.