Well, from this example, management side was unwilling to even invest time in exploring or acknowledging the idea that they might be wrong. I don't know about you but I don't want to work with people who you can't have a reasonable conversation with to get to the bottom of a problem and figure out the issues together. Everyone makes mistakes, sorting them out together and achieving mutual goals is what makes this sort of work bearable.

If management doesn't understand collaborative working environments, humility, and basic problem solving, I don't (and will not) work with them.

This was definitely true at a past job which happened to be a fantastic place to work. The HR recruiting team was well-liked by the executives and run by a founding member of the company (so had a lot of power and autonomy). But they absolutely tormented us with things like not telling us a candidate had canceled until right before the scheduled time (we could find their emails in the recruiting software from hours or days earlier), scheduling individuals for multiple interviews simultaneously because they didn't care about our time so put it on us to find someone else to help, and occasionally forgetting to book a conference room forcing us to scramble and generally look bad.

The only satisfaction we got from the whole situation was reading the furious reviews the candidates would write on glassdoor.

No, but their skill at being inconsiderate assholes almost certainly transcends the interview process as well as their engineering process. It likely permeates their whole organization. That's what I think the interviewee is looking at in this case and that's what was found. Unfortunately, fixing inconsiderate asshole syndrome is close to impossible. I wouldn't want to work at a place filled with them as described by this interviewee's experience above.

My opinion is based more on the final sentence than on the borked exercise.

Everyone makes mistakes. Character is revealed in how one handles it when the mistake is pointed out in good faith by a party who has a perfectly legitimate reason to do so.

If someone giving you an interview problem isn’t mortified that the entire premise of their result is invalid because they didn’t even bother testing the code, I would not want to work with them.