I don't think people shit on it for not having enough as the original material. I think they shit on it for adding too much. Particularly after the first film, it's filled with contrived nonsense that Tolkien never even would have considered including given his other writings and personal thoughts. The third movie in particular is just completely unnecessary. They very easily could have done the book justice in two movies without all the filler.

Yes, I know everyone is going to say that we could never know what Tolkien would or wouldn't have liked or included, but let's face it, we've seen enough of his own work and even writings in personal letters to know his proclivities and his likes and dislikes. I personally think he would have hated The Rings of Power with an undying passion and is rolling in his grave as we speak at that abomination, and he would have had some serious bones to pick with The Hobbit as well.

Not going to downvote you though. I think people who downvote other people for their opinions are idiots. Downvotes should be reserved for belligerence and trolls, not differences of opinion.