If they have no problem being told to wear clothing in public, that they need a shirt and shoes in a restaurant, that they need a hardhat on a construction site — then they have already agreed that it’s acceptable to be instructed to cover part of their body under given circumstances.
They are not nudists. They already cover up according to regulations determined by others. It’s no different.
Freedom to do what they want does not include freedom to put others at risk. They need to shut up and mask up. Or go home where they don’t need a mask.