Keeping in mind the context of the original parent comment, yes it is 100% standard to ask about the "hardest day of your [working] life." I wouldn't ever put it like that, but asking about difficult challenges and how you overcame them is completely normal. The blog post reads to me as someone who is oblivious about the subtext of these questions.

When I ask that kind of question, I'm not asking you to share about a breakup, or death of a parent, or some other non-working issue, and I would think it very inappropriate for you to do so (thus, the quick rejection email). Instead, I'm asking about how you navigated losing all your code due to a backup issue or how you dealt with a difficult client or coworker or even some problem at work that threw you for a loop for weeks. That's the subtext of these questions, as the original commentator also made quite clear.