OK, so basically humanity so far was in the wrong for not wearing masks for cold, flu, and every other transmissible disease, and we should wear masks forever in public?
Long before covid mask wearing has been an insanely common thing to do when you're sick.
Masking in flu season isn’t uncommon in some parts of the world, and it was a lot more common during the 1918-1920 pandemic, so, “humanity” as a whole is not a constant.
Cultural variation aside, different respiratory viruses have different combinations of infectiousness and deadliness and responses to various countermeasures, so their are rational reasons the reactions to each, given a constant utility function, would differ. The common cold, the 2019 seasonal flu, the 1919 pandemic flu, and COVID-19 are all very different things.
Also cold/flu cases are way down due to people masking up and cleaning hands.
A lot of people complain about seatbelts being uncomfortable during driving, and yet its a law to wear them. Why?
Oh yes, I too take sick leave when I have runny nose until its gone