That is indeed correct, it's a pretty logical point as well, but I don't expect anti-vaxxers to accept it. Let me also point out that it's not the first time masks are introduced due to a pandemic, they were also used during Influenza, in 1918, with conspiracy theorists still acting clever back then. On top of that, in China, even before Covid-19 appeared, it was common to wear a face mask in public, even if you were simply sick with the flu.