Perhaps in other words, you are guaranteed a few bad interviews. Interviewing is very random. I have sat on both sides of the table. I have sighed when other interviewers have bought up minor quibbles about otherwise excellent candidates. There are a lot of really bad interviewers. Getting interviews at a bunch of places that really desire to hire you somewhat lowers the crappy interview percentage.
Yet another way to put it is you are practically guaranteed a bad interview. It is best to accept that and move on. I had what started out as a really great interview process go bad when I went on-site. It happens. The randomness of the interview process and the fact we're all human/fallible practically guarantees at least one bad experience. My bad experience really bruised my ego but ultimately, I realized it was a good experience too when I framed it in the context of the overall experience.