No one is saying that people who work in, say, a burn unit, or a serious infectious disease unit, shouldn't use appropriate measures to prevent infection.
Public mask mandates mean people making all the time, and there is no evidence that is effective, no matter what kind of method you mean.
You might as well talk about perfect use stats for contraception, totally useless for creating policies.
Proper masking is not easy or simple and not something people can fudge. It means a fitted mask, used for only a few hours, not touching it, not reusing it, not putting it in a pocket, not pulling it down even for a moment and then replacing it, not allowing it to touch a surface.
And what most people use, surgical or cloth masks, are just useless from the get go.
There are a lot more people being misled about how effective the mask use they are actually doing is than there are questioning proper use of masks in limited settings.