Have to weigh in on this, since I think it gets right at that juncture between appropriate and PC gone awry.
I think doctors should be free to tell us things that relate to health, even if these things happen to also be social issues around which there is discrimination. Obesity is one of those things. Smoking could be considered another. Many smokers may view their doctors as being judgmental when they bring up the smoking issue, but your doctor is not your friend, is not (hopefully) being judgmental (this is not always true), and should be free to be adamant if necessary about behavioral change you should make.
If the doctor in this article spoke about attractiveness and finding a new partner, however, I agree he went too far. This is judgmental, its focusing on weight as an issue of attractiveness, not health, and it reflects a bias on the part of the doctor. Worst of all, though, it alienates the patient, makes them feel bad, and is worthless in creating the essential motivation to change behavior. In effect, it totally backfires and hurts other doctors who need to have the freedom to comment on obesity as a health issue.
Also, I have to add this. I taught Health Psychology at the University of Georgia, and one thing that research shows that I do believe all doctors could benefit from knowing is that FEAR TACTICS DO NOT WORK unless they are paired with a simple formula for change. Simply said, if you plan to scare someone with a statement of the potential harm of their behavior, you better be ready with a formula they can follow for changing it. Otherwise, all you do with fear tactoics is create a situation where the person feels the need to justify their harmful behavior ("what I'm doing isn't THAT extreme, that'll never happen to me!"), which equals continuing it AND NOT LISTENING TO YOUR MESSAGE ANYMORE. Bad outcome.