Because you are implying that these things dont work by stating the science hasnt gotten there yet. When actually much of it has. The full mechanism and how virulent and all the mutations and who gets affected and infected and why isnt fully understood sure. But mask wearing has been tested and does reduce the viral load, close proximity to an infected increases exposure, touching contaminated surfaces and not washing hands reduces risk, viral load due too poor indoor ventilation are all known exposure risks for this or any other virus. You should be discussing more the scientific issues with coming up with a vaccine and why some besides age are more at risk than others... That is not yet figured out fully. And you have discussed some of that but you still imply doing all the above is not full proof. Actually it is, just we as humans dont do it perfectly and make mistakes or simply ignore the above. Cook your meat as well kills viruses and bacteria. Bleach wipes works. I was in a high viral area made some little mistakes and caught it. Luckily I survived. Still I didnt spread it to my family because I quarantined early, wore a mask at home even before symptoms and I still wipe everything down when I come in. It is tough to change behavior, I get it. But much of this could be ameliorated if folks would just do these basic things.