It depends on the context. If an overweight person is at the doctor, it would be very appropriate for the doctor to discuss it. Some people, like Whitney Thore on "My Big Fat Fabulous Life" embrace the term fat and describe themselves that way. If you go up to a larger person and insult them about their weight, that would not be appropriate. That would be bullying. The same way if someone went up to you and said "what's wrong with you? Why don't you talk? Cat got your tongue?" But if someone simply said "joe is very extroverted and outgoing, while Shadix is introverted" that is not an insult. It is a description. I'm a professor and me and several of my colleagues describe ourselves as introverts or refer to each other that way. We do not find it insulting because it is true.