Bingowings said:
The fashion for disliking The Hobbit is like the bashing Quantum of Solace got after the almost identical Casino Royale and before the almost identical Skyfall. It's just a popularity blip.
That's taking things too far in the other direction. People who are disappointed by a mediocre film that pales in comparison to related films tend to exaggerate their dislike, saying it was awful/horrible/unwatchable, when its only real fault was being dull. I'd agree with that*.
But to suggest that the dislike for the films is due more to the popular mood than an actual assessment of the film itself, well, that's just wrong. People just disagree on whether films are good or not, and sometimes you will find yourself in the minority. Just ask me about Cabin Boy sometime...
*EDIT: This statement is not to be interpreted as applying to the Prequels! No, those were well and truly awful.