Because I hear these people make the masks don’t work argument
The thing is that they hear doctors say “Masks don’t reliably protect against disease” and go “masks don’t work”, but what the doctors say is “they aren’t 100% reliable, so don’t use it as the only method of protection”.
But if wearing a mask vs not wearing a mask lowers your risk of infection by 50%, that’s a huge deal! And with the way infections spread, that’s millions of prevented points of infection.