You seem to conflate so many things here. Doctors wear mulitiple types of masks. Surgical masks (as are recommended for the general public) prevent a doctor from spitting on a patient accidentally (just as they prevent an infected individual from expelling virus laden spit droplets). Surgical masks provide limited (if any) protection from airborne droplets. Rather an N95 masks (with a seal and filter) is used. To make this effective to protect the wearer, goggles must also be worn. The general public does not wear goggles. Further,training on putting on and taking off masks is provided to medical professionals. Face shields protect from yet another class of dangers (splashing of contaminated fluid). The general public has little reason to wear these.