It sucks that you (and numerous others in this thread) have had a bad experience.

As an ex-Amazonian that did my fair share of interviewing, I can share additional context on some of the above:

* Tardiness and just the general unprofessional handling of someone being interviewed: At least in the area I worked this would have been unacceptable and the interviewer would have had a very uncomfortable conversation with their leaders. I can't imagine a repeat offender lasting long. There was a huge emphasis placed on the importance of the hiring process, the importance of doing it well, and that finding the right people was about the most important thing to be doing. Obviously at a company of >700k people it's not going to be a consistent experience across the board.
* I learnt this from various forums before I attended my own interview so it's not exactly a company secret: but yes, each interviewer is told the LPs they'll be asked to assess. You're expected to spend the full 55-60mins asking questions on those LPs to maximise the change the person gets the job. It's too easy to burn 20mins talking about hobbies and ultimately that's not going to help the candidate get the job. Even worse is that if there's suddenly some shared interest and experience that conversation derails into enjoyable but more unproductive conversation. The feedback skews to "I like this person" and is filled with bias vs "here is the examples for why they'll be successful here".
* The standard set of questions is a leveller to give everyone a consistent experience and try to reduce the likelihood that someone gets a job just because they interview well.
* Likewise the seemingly unrelenting questioning that's effectively trying to gauge examples for just 1-2 LPs in my experience provides a fairer experience to most other alternatives I've experienced. People with pre-canned answers that they're able to spin nicely start to fumble when people want to keep digging into the details on the same thing for more than 5mins. Conversely people who struggle to think of the right words off the top of their head, or are especially modest about their accomplishments, don't immediately suffer. They're given a time and space, and ideally a lot of guidance, to expand on things.
* There's no quota the amount of notes you need to take. However, the debrief for every single interview loop I was part of was always 30-60mins. You don't get to show up with some vague feelings about what the next step is. You need to come with an opinion, with the evidence to support it, and not waste every other interviewers time. If you disagree with another interviewer you need to be able to point at the specific evidence you have either for or against the candidate. We'd often be told "absence of evidence is not evidence of absence". You needed the evidence for whatever point you wanted to make, otherwise you've just wasted the candidates time.
* The rigour in the post-interview process and debate, which builds upon the foundation of all of the above activities, is ultimately what it's in service of IMO. Every candidate gets case heard with all of the most compelling evidence that can be provided. I've been involved in debriefs where all but one interviewer came with a "not inclined/do not hire" decision. The discussion and debate that ensued and the recalibration from the collective notes ultimately flipped everyone to a hire. I'm pretty sure every other company I've worked at would have had such a debrief be over and done with in a couple of minutes and we'd move on to the next interviews.
* The other part of this that's not always immediately obvious is it's a pretty binary assessment. You can either do the job or you can't. If you can, as determined by the debrief, you get an offer. So first through successfully wins. There's no stack ranking candidates against each other and trying to apply some subjective assessment of who is in a relative sense the "best". Which is again why there's such a strong emphasis on consistency, removing bias,

It's definitely not perfect. It can skew very heavy towards feeling impersonal and like the candidate is being interrogated for an entire day. The thing I missed most about vs other places I've worked was the interrogation feeling like a reinforcement of the power imbalance inherent in a job interview vs levelling the experience and making it just as much for the candidate "would I want to work here/with these people?". But on balance it's probably the most consistent and fairest approach I've experienced (when properly executed, which it wasn't for you, so I'm sorry you saw the worst of it).