But that's only in cases when there's a lot of contact between the patient and the doctor. And you don't have that so much with the doctors you meet when you have to go to a hospital, as they treat hundreds of patients. Or with a general practioner who has hundreds of patients too. Or even a shrink who just spends an hour with a patient for a session.
But it's a professional distance probably. Although not every doctor is like that. I've met (especially younger) doctors who you feel you make more of a connection with.