I think this article's audience is teachers of beginners, not beginners themselves. At least the author is writing about their experience as a teacher.
Don't know why you thought it would be an article for beginners, but good on you for linking a resource regardless.
The article is an introduction to the basic concepts of Haskell, thus beginners may be considered a target audience. However, the style and the content brings to my mind the dreaded monad tutorials. I'm not convinced the article is about pedagogical downsides of specifically Haskell. It mostly reads like a collection of random purported gotchas/differences from someone with experience with other languages.
Don't know why you thought it would be an article for beginners, but good on you for linking a resource regardless.