I totally agree with you. Some of the content there seems relevant to CS in general, but I hate the fact that you need to study content that you won't use on the job in order to pass an interview. It doesn't make sense to me. I've seen new grads perform as well as senior engineers with these Leetcode-style questions so I've stopped using them to assess engineers. Further, I know we're specifically trying to assess technical ability in an interview, but that's not the whole picture for an engineer. They need to be able to take feedback well and provide good mentorship also. I think we miss this.
Inspired by some realistic interviews that I did recently, I've been working on something[1] that aims to equip companies to hire engineers using realistic assessment methods. It scales like Hackerrank, but I think it's fairer.