AngryVoter
It's great that you're thinking critically about the ways that this individual study might fall short, but trying to poke holes in a study here or there does not undo the (literally) century of research underlying the efficacy of cloth masks in preventing the spread of airborne illnesses (or epidemiology in general).
Today there's the "Let's actually do our jobs and keep the country running" party and the "Let's destroy our country and blame it on the other side because corporate lobbyists pay us to do so" party. And somehow we need to find common ground and unity when the other side is more interested in bullying and obstructing the Democrats than it is trying not to kill another 200K people. There's compromise, and then there's calling a spade a spade.
To be clear, I won't pretend the Dems are fine (and if there were a way to vote third party without throwing away my vote, I would do so in a heartbeat). But the Democrats aren't even particularly progressive anymore. Bad-faith concession after bad-faith concession to the GOP over the course of decades has slowly dragged the Democrats to the center, while the GOP's actual extremists making a mockery of our democracy have the gall to label providing healthcare as the real extremism.