Covid is down/non-existent in counties in Western Kansas too where nobody is wearing masks.
These "studies" are worthless because they contain so many lurking variables. They do more harm than good because they distort reality and "cry wolf", weakening the public response when compliance is needed elsewhere.
I'm not saying don't wear a mask. The best studies we have so seem to suppport they slow disease transmission. But we shouldn't let bad science get a free pass.