Same as the vax, if your vax doesn't protect you from someone else, it's that vax that doesn't work, and it won't work once you've vaxxed the other person either.

If your own mask doesn't stop the virus and doesn't work, neither will it stop the virus when someone else exhales.

I mean, how much of a retard does one have to be to believe mask mandates are going to do anything other than remove the freedom to breathe without growing fungi and bacteria?