I think that's true to some degree but most types of doctors still require going through an internship (sometimes), rigorous and lengthy residency program and passing their specialty boards.

It's true if someone can do those 3 things without going to medical school they may be missing a great deal of knowledge passed from medical school that maybe they were not explicitly tested on or experienced in the field. I'm not sure what to do about that. If you could find a solution for that then banning from asking or considering education could actually work, I think...but that's a hard problem to solve.