It's one of those things that after a few years you look at and wonder why there's string and String, int and Int32, you google it, you find out it's simply an alias.
So he's probably only interviewed juniors.
I'm sure many people would prefer to get the wrong answer in interview than imply the interviewer's premise is wrong. That's why trick questions are dumb in interviews, they ignore the power dynamics in play and how someone will be judged if they seemingly "fight the interview process" (by calling the question(s) flawed).
In normal conversation I'd likely call it an alias (without 100% certainty) but in an interview I'd prefer to be wrong than to imply the interviewer's question is flawed.
TL;DR: All the blogger proves is that they're a bad interviewer, not that they're interviewing bad programmers.