Lol. Show me someone who can solve these problems under interview conditions after taking a freshman algo course, without further practice and I will show you the greatest genius who has ever lived. Humans are not that smart. But they are tricky lying assholes who will pretend to have not practiced if it advances them.

Anyone who participated in IOi/ACM ICPC can crack them easily

This is literally practice. What part of my comment caused you confusion? (I cannot repress the snark, but you are performing some pretty intense mental gymnastics to support some internal emotional state)

And why do you think practice is bad or people are not supposed to practice?

Would you hire someone for a highly paid job with literally no experience/practice?

We appear to be living in alternate realities and each be having a different conversation. Perhaps the time streams crossed or something.

There's plenty of us professional devs out there who never went to uni, so is leetcode designed to eliminate us? And since we didn't go to uni, we learnt what we actually needed for whatever job we happened to do, which (surprise, surprise) has very few algorithms (web dev). Most algo problems are abstracted away behind a ready to consume library, so if you want to quiz me on stuff I've never made, and most likely never will, that's kind of dumb.

But then again this is the same logic that gave us google doc coding interviews so I'm not sure why I'm expecting anything at all ...

I am sure there are professional home builders/construction workers/house flippers who never went to college. I bet one can learn building house from youtube.

yet there are Architect/civil engineering degrees and large engineering firms that design and build skyscrapers/bridges/industrial facilities that require quite a bit of formal training.

both of these engineering subtypes can coexist, same in software

As someone without a CS degree, I was quite happy I could use a week worth of algorithms training / practice to prove my suitability for the industry, rather than have to go through a whole formal degree in CS.