Masks are required in all public transportation and terminals in Sweden. Sweden, which country has a very small population, didn’t do all that well with the epidemic, either. And Swedes tend to be traditionally very socially distanced from each other in public.
I think that misses the point. We're talking about herd immunity in Sweden.
Assuming that you are correct and that the Swedes required masks on public transportation (big deal) and that the Swedes are more socially distant(sounds like a reach), all of that would only mean that the Swedes delayed their herd immunity and that they could have done it sooner.