> It's something that forces everybody to visibly declare an affiliation with a side at all times in public.

No. Forcing people to wear a police badge or a yellow star or a hijab or a a beard in some places would fit that outlook but the first reason to wear a mask is a medical/prophylactic one. The fact some people (right or left) decided to associate that with political beliefs is another matter that has nothing to do with the inherent advantages that wearing a mask provides in some occasions.