If somebody is a doctor honoris causa, has been seen as deserving to be doctor by the only group of people that can legally grant this titles.

Anybody with a doctorate can decide to use the title, use it only in an ironic way, or just don't use it, as you wish. "Dr. Clint Eastwood" would not be a symptom of anything strange. Eastwood is clearly an expert in films, successful at both sides of the camera, so... why not recognize it?