Many emergency room doctors tend to focus on crash aftermath and react to stop people from doing whatever led up to the crash - including discouraging cycling.
Other whole-health doctors look at the big picture and understand that the health benefits of activities like cycling far outweigh the risks, even when commuting in moderate traffic. Cycling is one of those activities you can do your whole life, for sport, exercise, fun or utility. How many high school football stars are still playing football daily when in their 70s? Some in the medical field really "get" this.