I dont think doctors are automatically authorities on evolution. Most doctors don't really need to study evolution in any depth, and some may have no education about evolution at all. All they need to know is about human anatomy and medicine.
If anything I reckon veterinary doctors will probably have more authority on evolution than regular doctors.
"All they need to know is about human anatomy and medicine."
It is because so many agree with this statement that so many doctors are just plain lousy at healing people.