I find that quite a few of the people that excel at science based professions such as medicine are very concrete thinkers. A+B=C. If a condition is exacerbated by obesity, remove the obesity and the problem is solved. The thing is, getting them to see the obesity as a problem in and of it's self is difficult, because doctors are like everyone else; many of them have been taught throughout their lives that obesity is a weakness and not a health problem.
I had a fantastic doctor from the time I was about 7 until last year. He treated me and my dad, and went out of his way to find answers for both of us, and never assumed my problems were related to my weight (For the record, the only health problem I've had that could be weight related is kidney stones, other than that I've had perfect bloodwork even well up into the 400 lb range).
My new doctor has never commented negatively on my size, and I go see him about every 6 months for blood panels and I had him refer me to an obgyn just to make sure that PCOS wasn't part of my problem. He's never made me uncomfortable, but he insisted on testing me again for diabetes this past month during my kidney stone struggles, based on one symptom - that also appears when you have stones. I didn't kick up a fuss. I let him run the panels, and when he said "you don't have diabetes" I simply said "I know, I didn't have it in April when you ran my blood work last either".
He wasn't being mean - he just did the math in his head based on the symptom and my weight. Really, that's what he's taught to do.