TL; DR version:
It isn't fair to throw a company out of a windows because they are serious about their hiring process. It totally depends on their company's growth need! First bullet point is extremely fair but the rest aren't and I agree on that.
Longer version: A lot of hackathon projects become startups and many of them don't require any algorithms. They can use libraries from Python and Ruby to do things they want to do. They can get away with a couple n^3 in their code and customers are okay as long as the service is stable.
And then there are startups out there building products using real algorithms that really require the knowledge of graph and sorting, dynamic programming and etc. If they need an engineer that can build on top of existing algorithms, then that's what they need.
I was a former intern at Mozilla and my interview was very simple and I really appreciate that. But what I do doesn't require me to know any sophisticated algorithm. I can survive with knowing Python and getting around with my brain. But interns on Firefox, servo and Rust probably had to face harder interviews, more tedious algorithmic types (although I heard most of those are basic too, like linked list and talk about C++).
I am also looking for new internship this winter and I fear these algorithmic interviews too, but some companies have serious need and they need people who can at least implement a linked list is important. I don't bother to read what their needs are.
I did roll my eyes when I looked at "3 hrs", "4hrs". That's a lot. But the first item: you don't even know how to write a linked list using your favorite language? Then that's the end. Linked list is not hard - you are not writing in C++ in this case.
The 7.5 hr is a different story, but I won't trash at the first point.