Funny, i think excluding Harry Potter makes it more accurate... those were objectively not well written books. Successful, absolutely and inarguably... but not good, certainly not masterpieces.

It's a list of "Masterpiece" book series. Just cuz Harry Potter was very successful, does not mean it's quality writing. it's full of obvious plotholes (like timetravel that is only used in one book, for example and then just ignored) and just bad storytelling.