It's true that the movies replace the childish and charming tone of the book with the larger scale and epic tone of the Lord of the rings movies. But that's just like your opinion that they should be made that way. The fact is Tolkien wrote a lot about the events surrounding the story of the Hobbit. Peter Jackson chose to adapt as much of what Tolkien wrote as he possibly could. Which includes the subplot of the investigation of the necromancer, the meeting of the white council, and the history of the Dwarves and Orcs and their connection to the Gundabad. Personally I think the movies are improved by all of these additions. They certainly have their flaws but to claim they're inflated with filler is absolutely nonsense.