I just find it way too early and easy to claim that all (or most) of the relevant experts have gotten it wrong on this one.
I get that your calculation puts comparably little weight on the health, life and well being on others. Most people come at this from a different perspective. With your starting point the calculations might have been different, that doesn't make them wrong at the moment.
I prefer a society where leaders and technocrats puts a high value on the life and well being of all its citizens. Based on that I think the shutdowns look reasonable. Though there's so much to learn about handling a pandemic like this in the modern world I'm open to us looking at it differently when this is evaluated at some point down the line. This will probably happen again so learning would be a good thing.
I would be more worried about what governments could put in place if this was allowed to develop freely over a period of months. Failing health care systems, failing institutions, many people having lost family members. That's when irreversible systematic change and extreme politicians would start to look paletable to a larger portion of the population imo. That would be the greater threat.
I think we might have quite different views of how this would look if allowed to spread freely through. Unfortunately there might be one or two examples where we find out what that looks like.