I honestly don't understand what movie the people who are giving positive reviews saw.

The main Harry Potter series was, of course excellent. Fantastic Beasts was a really fun sequel that introduced us to a bunch of cool creatures and showed us a different part of the Wizarding World. What did this movie bring us? A lot of boring scenes, an incredible amount of "who is related to who" and some pandering to fans who get excited by seeing characters who they've been wanting to see for years, but very little excitement, no character building at all, and basically just a lot of filler.