You pick one element of that context (no hard mask wearing rules) and conclude that it must be because of that when it's much more likely that other elements (o

You pick one element of that context (no hard mask wearing rules) and conclude that it must be because of that when it's much more likely that other elements (or their combination) would explain the result. For all we know, if Sweden had a more stringent mask wearing rule they might have had even fewer cases and deaths.