Wrong about what? That they are easy? If you know binary search, sorting, sets, hash tables, recursion then it is easy. If you wanted to make it more aligned with what a developer does day to day the alternative is doing a small project in your own time which is more time consuming for everyone.

But, then there's the ones that are all about specific techniques such as dynamic programming + memoization, or specific graph algorithms etc, etc. Any decent programmer can learn how to do these harder problems under time pressure (interview) through practice, but this is really about Leetcode grinding prep... these are not problems you would likely encounter in most jobs, and in the real world you'd just Google for algorithms or ask a colleague if you needed help.

I'm not sure that logic alone is a compelling: It's conceivable that this secondary industry addresses a real gap in university curricula, or a need for ongoing training of experienced developers.

But I think your overall point still holds, because there's a consensus that a large number of Leetcode-like puzzles require familiarity with problems and solutions that hardly every come up in real professional software development, and aren't even good proxies for the abilities that do matter.