Barely a century ago, it wasn't common for doctors to wash their hands, because it hurt doctors' feelings. Dr. Charles Meigs, an obstetrician, said, "Doctors are gentlemen and a gentleman's hands are clean."
But, of course, factually they weren't clean, factually they were full of germs, and factually Dr. Meigs was killing several of the people he operated on through his unclean hands. There was factual data that infant mortality dropped significantly in clinics where doctors were washing their hands.
But the response to hand-washing was much like yours. "You're saying society should keep washing hands everywhere literally forever? That's so insane I can't tell whether you're even serious." And in fact they sent the doctor who suggested hand-washing to an insane asylum, where he died.
https://en.wikipedia.org/wiki/Contemporary_reaction_to_Ignaz...