An incredible display of disrespect? It might be rude, but that’s about it. Depending on the tone of voice, it could have been intended as a way to relieve the author’s tension.
It does sound a bit annoying, but if that is the author’s worst interviewing experience, it’s not that bad.
On reading it my thought was the interviewer was making a small joke to put the author at ease: "Ah, you've forgotten some semis, you're probably writing a lot of swift at the moment, it's okay". But he was in the room and I wasn't, so I can only trust his interpretation.
It does sound a bit annoying, but if that is the author’s worst interviewing experience, it’s not that bad.