Ofcourse the interview process is (or atleast is supposed to be multifaced) and passing these problems is just one of the facets of the process. A great candidate can bomb one of these questions but I wouldn't necessarily reject them just because of that (although that happens in practice in the industry) and wouldn't necessarily okay someone just because they aced one of these questions.
I'd take complaining about these type of problems any day over complaining about only being able to get a job in certain companies by having connections or having gone to an Ivy League school.
There's a vast territory of approaches that are neither leetcode hazing or culture fit tests. And which, while nuanced, are basically objective.
Work sample evaluations do quite well, for example. As do in-depth technical discussions about ... just about any subject the candidate claims to know about.
Neither of which have anything to do with "culture fit".
Having attempted to do this after reading all the HN screeds, I found that this failed horribly. You'll find a large number of people who seemingly know the theory, but can't execute worth a damn. They can happily talk on and on about normalization, regularization, imbalanced datasets and so on. Then they fail fizzbuzz.
I then put the programming screen first.
How do you compare candidate A with preferred subject 1 with candidate B with subject 2? And how do you get the candidate to talk sincerely and not bullshit around the topic, especially when testing ML - a modern alchemy more or less, no definitive answers, just a bag of tricks?
I have had problems with controlling the waste of time and directing the talk towards useful topics because the candidate wouldn't stop the bullshit talk. Maybe other fields have less bullshit maneuvering space.
I think it's better to go with a list of basic questions that remains the same between candidates. Only if they ace the basics I test for depth. Depth can be tricky to evaluate, especially for people who are not very bad - maybe just in ML.
As someone who has a current stable employment I have the freedom and flexibility to fail at numerous interviews with only minor frustration of time wasted. If I were out of a job and a bit more desperate I would just lie through my teeth on all elements that of a job interview except education and employment history like a super brown-nose narcissist. Since most all programming interviews are maximally subjective intentionally injected bias goes both ways and is easily applied.