DD has similar attitudes. Ever since she was tiny, she complained about adults who crouched down to talk to her 'at her level' because she said she found it condescending. I once explained that this was standard advice for people working with children, but she was having none of it. And she loathes when people talk in a 'baby voice' when speaking to her.

Now that she's 11, the problem is resolving itself, and our primary care doctor, dentist, and optician are all great and basically treat her like an adult.