Even if 2020 hindsight reveals the lockdown wasn't right, it was still the right choice at the time
A frequent question I've seen these days is, "Is the lockdown worse than the disease?" The lockdowns are hugely expensive, and there are even many arguments that they will also result in large numbers of deaths. Some even advance that the death toll of the lockdowns will be higher than the toll of the virus. The economic cost is high and not evenly distributed. In addition, other diseases with similar death-tolls are survived without lockdowns.
Some also speculate that the virus will turn out to be not as fatal as predicted, or more or less virulent.
There's lots of debate on these points, but I want to sidestep that, and stipulate, for the purpose of argument, that this theory is correct. Let's presume that we learn, when it all winds down, that the lockdown was a big mistake.
The question becomes, was it a mistake to do them back in March, when we knew less than we know today? It might be possible for the lockdowns become wrong in hindsight, but nonetheless still correct, because you have to examine the question of decision making with imperfect information.
In February and March, we had many conflicting pieces of information. We saw what happened in China, and had some data from cruise ships. Italy's horror was underway. Unconfirmed rumours were circulating, yet to be confirmed or refuted, of true horrors in places like Iran. The success of the lockdown in China was starting to show, and success in Japan, Singapore and Taiwan was showing its beginnings. Credible scientific sources had quite varying numbers on the mortality rate of the disease and the R0 exponential spreading factor. Some sources predicted millions of deaths, others predicted the problem would not be that bad. Various people had arguments as to why any given theory was right or wrong, but there was no consensus.
Officials, and the world faced a difficult challenge, given all these arguments and reports. Most of them, I would venture, made the right decision.
If they did not order a lockdown, and the projections of massive death came through, they had failed to prevent a catastrophe with millions of deaths.
If they ordered a lockdown, and the virus ended up mild, they would have triggered trillions in losses, including some deaths, but by all evidence, far fewer than a bad virus outbreak would cause.
This seems like a fairly straightforward choice, regardless of what we might or might not learn later. To not lockdown when there is a credible risk of the death of millions is just not an available choice. Bad as the consequences of a lockdown might be to the economy, they won't match that.
(Of course it would be wrong to compare the consequences of a lockdown with the virus death-toll under lockdown. We don't get to do the real comparison because there are no wealthy countries, and particularly big dense cities that did no lockdown at all, even Sweden shut off most gatherings and closed high schools and universities, and has most people trying to stay at home.)
Even if the Swedes selected the best plan, it was a risky bet they took. They didn't know at the time if they might trigger becoming like Italy. But we should naturally track the progress of every strategy, and adjust strategy as more is learned. Not try to imagine what we should have decided if we had only had more solid facts a month ago.