Japan is lying. They have been full of it since the very beginning as they tried to cling on to hope for the Olympics. I don't trust anything coming out of there.
Not commentary on masks at all. I think everyone should wear them. They cause almost zero inconvenience to the wearer. The trade off between "what's the drawback of doing it" to the potential benefit from wearing a mask makes it absolutely ridiculous and/or selfish for someone not to wear one. It's a piece of cloth over your face. If you have trouble breathing through cloth, you are in a very, very high risk cohort and you shouldn't be out of your house anyway.
I'm just saying Japan is lying.