People tend to not be super honest about your perceived negative qualities because it's considered impolite. If the doctor or whoever wants to know what people around me think of me, it needs to be given to those people as an anonymous poll.
e: This kind of question also assumes I interact with anyone to the degree that they have any idea what I'm like.
My point isn't that an anonymous poll is a good idea, but that expecting autists to accurately report on the (potentially secret) feelings of other people isn't practical either. It's like how they make you jump through a bunch of beurocratic hoops to get ADHD assessments. The test itself is filtering against positive identification in a number of cases.