If an interviewee said they'd do something, and then didn't do it, it would be regarded as an integrity problem.
Your example of the guy who made a mistake is certainly a bummer for him, but presumably he didn't know he was making a mistake when he turned you down. And that's got to be a very small fraction of hiring situations.
The problem wasn't that he cancelled the interview, it was that he made up his mind before a scheduled interview with me.