Why do you care that people are upset? Maybe realize people love Tolkien, and when they heard about the show they wanted it to be amazing, but recent expectations (especially from Amazon) made them weary, and the show has so far largely justified it.
RoP is a very pretty steaming pile of mediocre. The dialogue is abysmal, the characters range from terrible to good, it strays very far from the source material, and the plot line is all over the place in the worst ways, having little progress while having very nonsensical moments (including the suicide attempt by Galadriel to be saved dues ex machina twice).
The fact that a show with a billion dollar budget based on Tolkiens work is so mediocre at best pisses people off because with the right team producing and writing it the show could have been one of the greatest shows ever, and instead its forgettable generic fantasy.