You couldn't do anything about the virus and (perhaps) dare not do anything about the lockdowns. Yelling at people about masks was the easiest way for a lot of people to exert a degree of control that had been lost in their own lives.

I pity these fools who take responsibility for everything except their own behavior. 

 It's like the inverted Jesus syndrome: Trying to take responsibility for the fate of the world, but by cussing and cursing at people.