The interactions and power dynamics between people differ wildly from person to person. While an interviewer might be the kindest person in the world for candidate A, they might be a total bully for candidate B. I was bullied constantly throughout school snd, whatever cues prompted those kids to pick on me are probably still there, but adults are a bit more subtle, because they can hurt you in other ways. And this is on top of the day-to-day variations, because they might be hungry and the current interview is sitting between them and lunch or maybe they just got slapped down by their boss and want to punch someone or whatever. Based on my own experience, out of the typical 5 rounds of in-person interviews that I went through many times for FAANG companies, one or two ended up being a total shitshow each time, where the interviewer was condescending at best and I don't think they realised it or cared. I was told several times "how easy / trivial" the problem is and that "they're sure I'll have an easy time solving it based on my CV". Maybe the worst ones are when the interviewer smirks at me when they spot dome issue and I can't cope with that.

Now add to this a long streak of never ever getting an offer after dozens of such interviews in spite of putting myself through training sessions and mock interviews over and over. I'm sure I'd get in eventually, if I just kept trying, but do I want a job where I'll be asked to interview people in a similar manner? Even if I refuse to interview people as part of my job, will I really thrive in there? I'm certain this process permeates in one form or another throughout the company culture in various internal management, decisionmaking and promotion processes, but that's a separate discussion.