I think this mentality is actually wrong. I've definitely met good engineers who were rejected for jobs they were qualified for because of these questions, but I've never met someone who was extremely good at these questions who turned out to be a dud after hiring.

I don't disagree with the hate towards the current interview process at larger companies, preferring take homes myself, but I think it's harmful to say that all they have to do is "memorize a bunch of ... techniques" - they're going to have memorize a whole lot to get through the interview process. In the process of memorizing (learning) those techniques, you're likely to learn a lot about the foundations of mathematical problem solving.

I guess I'm biased because I studied math in college, but I think we can both criticize the current interview process without taking away from the hard work of people who are actually passionate about algorithms.