Earlier quoted context omitted.
If the candidate says they don't know a topic, that is a valid response. It's not worthwhile to ask detailed questions about the topic. That's a sign of an inexperienced and/or unprepared interviewer.
Asking someone "how many prime numbers are there?" seems pretty valid to me. It's an easy question. The two valid answers are: "a lot" or "infinite" (with "more than 10" also being a fine answer IMO). I'm not sure the interviewer was expecting the actually correct answer here (infinite) - lots of programmers don't know that there are infinite prime numbers - I think he was trying to set up for an explanation of an al…
However, for a web framework? Like, primes are pretty simple, but they're also pretty niche. What range of 'easy' questions that are not directly or indirectly related to the job are allowed to be asked? Can we ask questions about the correct leavening agents to use for different types of bread? I mean technically we're just trying to see how they cover up gaps in their technical knowledge. And all questions are 'easy' for the right people.
If you lure someone into a place with the promise of gainful employment and then waste their time with niche questions that are unrelated but you happen to have warm fuzzies about, then you should probably expect to get a bit of snark.