It's a common fallacy to believe people that are doctors (or have a PhD) are really smart. They know one specific thing really well, anything outside of that one thing they are as smart as any random person.

Specifically for medical, there's a few other reasons. Medical software is often garbage, a doctor's day to day experience with computers is not great. This doesn't make doctors want to learn more about computers. Doctors get trained by older doctors, so it's going to take longer for those that aren't hostile to computers to get into teaching and how to use computers in a beneficial way. This is just barely starting to happen, I doubt many teaching staffs are completely pro computer, but at least some are.