I've been involved with hiring (although at a company that's far from a household name), and the second half at least, sounds perfectly reasonable to me. They've taken the stuff he claims to know in-depth and explored it. That's the perfect place to dig deep. You don't take someone who has PyCon on their CV and get them to do fizzbuzz on a whiteboard - and there's no point getting into the weeds on topics they haven't even mentioned.

"What makes this candidate unique" is the best place to spend the meat of an in-person interview - and the best place for the candidate to sell themselves too. Its usually far too late into the process to waste anyone's time with asking every candidate the same stock questions.