I personally struggle to consider either of these studies a true representation of how patients react to doctors who have a more unusual look, such as dyed hair or piercings.
The main reason that I feel these studies are flawed is because they both assume that the ONLY way the patient will judge any doctor is by their appearance - that all other facets of the physicians (including experience, personality, bedside manner, type of communication, etc) will be ignored, which is very unlikely to be true, and I think it's a little ridiculous to argue that no patient would ever consider those factors when choosing a doctor.
Basically, these studies are saying if your ONLY way to choose a doctor was based on appearance, which would you choose? This is a flawed method as this is not the only way to choose your doctor. If I were one of the subjects in those studies, I probably would choose the more professionally dressed doctor, as based on the ONLY information presented (their appearance) the more professionally dressed doctor would be the logical choice. In practice, however, my favorite doctor is a male with long hair, has both his ears pierced, and wears khakis and hiking boots to appointments. Definitely NOT the professional appearance that most would expect, however I don't care what he looks like, because he has the experience, personality, bedside manner, and communication that I want.