I think picking countries to prove an assertion is more Ancel Keys cherry-picking than anything. COVID hits older populations harder. Sweden isn't following best practices with social distancing, but the other Scandinavian countries are. In some Asian countries, they're used to masks (Thanks to SARS and MERS) and just about everyone wears them in public. So it really is difficult to pick out one thing and make an accurate assessment based on a few countries. You can find any answer you want in the data.