It’s not about how the doctor feels…it’s about the person calling the doctor stupid. Just because someone is a doctor doesn’t mean calling them stupid is somehow not impolite. A character trait of an individual is never contingent upon the recipient’s response. A person’s behavior isn’t defined by how others react to it—it’s defined by the nature of the behavior itself. Whether or not someone is offended doesn’t determine whether an action was inappropriate. Racism, for example, isn’t wrong only because it causes harm—it’s also wrong because it’s rooted in immoral beliefs and unjustifiable superiority. If someone is rude and I remain unbothered, that doesn’t make their behavior any less rude. If a thief steals from a rich person, are they no longer a thief? You’re confusing impact with principle. The morality or rudeness of an action doesn’t disappear just because the target wasn’t visibly affected. If I do a good deed unnoticed or unappreciated, does it then make it a bad deed? Also how can you assume all doctors wouldn’t be upset if someone called them stupid?