Ah so a good interview question for a candidate is something that YOU have experience in.
Does that seem odd?
Do you think you would be an expert in something the candidate had experience in? Probably not. Should you find out how they speak about something THEY are experts in? Probably.
But like the OP said, tech interviews are about posturing so that the interviewer feels better about themselves.
does that seem odd? Not at all! How can anyone evaluate a someone else's performance in a domain if they don't know the domain? You ask the question many times over so you can judge performance relative to others. Yes, the interviewer should be familiar with the topic of the interview.
Does that seem odd?
Do you think you would be an expert in something the candidate had experience in? Probably not. Should you find out how they speak about something THEY are experts in? Probably.
But like the OP said, tech interviews are about posturing so that the interviewer feels better about themselves.