I would argue I know because I have done many interviews, not nearly as many as the author of the article. Most interviewer candidate are about as qualified as

I would argue I know because I have done many interviews, not nearly as many as the author of the article. Most interviewer candidate are about as qualified as a stuffed animal, except I would allow a stuffed animal in the office because they tend not to break things. I agree with you that on your points about books and project founding, but I would hear a candidate out and not make hard unchangeable presumptions. As for how do I "know" I can't know, I am only in the interview for an hour or two. The best I can do is get a sense. If the candidate nails fizzbuzz, explain the nuances of git v mercurial for 20 minutes and provides a plausible explanation for his previous place of employments toxicity then that affects my decision making one way. If it feel as though their reasons are thinly veiled excuses, they don't know foundational tools or fail at fizzbuzz... well I don't let interviews proceed to where people fail all three when they start with some minor points against them. Too many red flags and I call it done.