One good way of dealing with that sort of rudeness is to confront it directly, being extremely polite. "Excuse me???" with a directed look. "I'm not sure I understood you correctly, but did you really mean to imply..."
Yes, or just ignore it. Experience with non-neurotypical people, or other cultures, can help you learn how to just shrug things off that you could otherwise perceive as rude. And then you can shrug it off even if it was intended to be rude.
I think the intention though is to confront it rather than just ignore it to either help the interviewer realize its not acceptable, or just make them less likely to do it again.
Watch the walkback.