There are a lot of horrid movies and tv shows with mediocre to bad everything that still have cult followings. It's getting high ratings because the people who like it and wanted to see it are the ones rating it. By now if you don't like Twilight you're not going to read the books or see any of the movies, so your ratings won't actually come into account here. It's like if 100% of people who like Reese cups bought them, 100% would be satisfied with the product they purchased and think they tasted good. If 100 people who had never tried anything like a Reese cup bought them and tried them, the percent would be much lower of those who liked it. If they already know they like it going into it, they'll probably ignore plot fails and say they liked it anyway, even if it wasn't a masterpiece by any means. 88% is the RT rating for Harry Potter 4 even though they added some ridiculous 10 minute dragon chase scene that was never in the book and left out a bunch of other stuff that WAS in the book, but the fans still liked it, obviously.