IF you work in Stockholm you probably commute by commuter train and or bus into the city, where in Malmö you can walk through the city center in 15 minutes so biking or owning a car to commute with is the norm.
In Malmö most stores close at 5pm, and malls much earlier than in Stockholm so they are visited on weekends instead of whenever (this also sucks since there is nothing to do after work), FNM starts at something like 15:30.
It's just a lot fewer crowds and situations with close contact in general.
This is the most logical time to take measures, except for maybe the very beginning when it could possibly have been stopped.
They're taking a swing in the dark, with the potential risk of a very high per capita mortality rate. If the duration of immunity is short, they could kill a lot of people for little gain. They're currently running at seven times the per capita mortality rate of Finland.
The death rate per capita in Sweden is not much higher than the US. At ~33x the population the US has ~25x the deaths. Given the US had only double the total cases on March 6 as Sweden that seems like a positive indicator for Sweden's approach. It's like saying it doesn't really matter what you do so you might as well stay open. The timeline of when you started taking things seriously is also a big factor of course. I think it's way too early to declare anything yet, but I think it's good there are different approaches being taken to learn from.
It should be noted that this is just the capital, which currently has something like 10x infection compared to most other areas of Sweden, and almost 20x the number of dead. To give some number, Stockholm has in the latest report 7k infected and 1200 dead. Malmö (or rather the region around it), which is Sweden third largest city, has 600 infected and 60 dead. Population wise, Stockholm has about 2x compared to Malmö.
People are not sure why stockholm has the number it has compared to other regions.