The issue is that we didn't know the virus was aerosol (airbone means something else). The best evidence at the time was that it was droplets. In the case of aerosol, just being in the vicinity of where an infected patient was, was enough. Washing hands has limited effect on aerosol since it "hangs around" in the air. The issue is that the virus also uses droplets. Coughing and breathing both spread. It was effective against one form of spreading, not all. With time we learned. That's how science works and expecting anything else is ripe for disappointment.
