I think it's sort of a litmus test for assholes. It's a relatively simple, but mildly annoying, thing to do that evidence overwhelmingly suggests has at least some impact on dulling the spread of the virus. You could just shut up and put the mask on, or you can make it crusade to argue against it and confront retail workers when asked to put a mask on, etc.
The lockdown thing I understand, as it has a major impact on people's livelihood.