Earlier quoted context omitted.
Hiring does need to avoid hiring idiots, but I've found that it's more effective to ask easy questions. Seriously. People who can't program a digital computer have just as much trouble, and there's less opportunity to fake it. Easy questions produce better signals.
I was asked once during an interview to describe a specific problem that I enjoyed solving. And I was told to go in as much depth as I could during the timeslot. I thought that was a great question. It got me talking about something I cared about, knew very well, and showed my normal thought process and development process outside of an interview. It also gave the interviewer plenty of things to ask about, to "quiz"…
I had recently published a (terrible, but also terribly fun to write) JavaScript physics engine, which the interviewer saw on GitHub. He began with, "how does it work?" and then continued with probing questions, getting deeper and deeper into the various problems I solved while developing the library, especially focusing on tradeoffs between various choices.
By opening the discussion on "my turf," he put me at ease in the conversation, but by driving the interview with very technical questions, he also got the answers he needed about my technical ability.