100% interviews are about communication and demonstrating thought process; after going through some rounds of interviewing candidates myself, any candidate who can adequately explain what they're thinking and how they arrive at their conclusions will be able to demonstrate their skills much more thoroughly than 'just use Postgres'.

That being said, it's also on the ones giving the interviews to push the candidates and ensure that they really are receiving the applicants best. The interviewers don't want to miss potentially great candidates (interviews are hard and nerve-wracking, and engineers aren't known for their social performance), and thus sometimes need to help nudge the candidates in the right direction.

Fully agreed on the point that interviewers should prompt and push candidates in the right direction.

The best thing someone can do to learn how to perform well in interviews is to sit on the other side where you’re interviewing candidates. Some candidates will get stuck on arguing some irrelevant point or trying to fight against the interview question for too long in an interview. Once you see how much it hurts the interview process you learn to never do it yourself.