Most of America doesn’t do it, just the people who are afraid of violence - which also happens to the same people who would quickly resort to violence. At this point, seeing a person wearing a gun is the same as seeing warning colors on other species like insects. If you see it, turn and go the other way. There is literally nothing worth the inconvenience of dealing with those people. (And hospitals don’t allow open carry so matters of life and death can be attend to without worry.)