To name a few reasons.
1. bad science (I know the real Star Trek would stretch things when necessary, but a galaxy threatening supernova was just retarded.)
2. idiotic plot
3. Destroys features which were intentionally put into Star Trek to distinguish it from low brow scifi
4. references to the real Star Trek come off as tongue and cheek parody
5. This ^*&( is put forth to replace the real Trek in production
6. They put a (*&^ing propeller on a spaceship
7. The Kelvin, Nero, and future Spock are supposed to be from the real Star Trek timeline, but they really don't fit in.
8. They gave Scotty a midget sidekick WTF!
9. An implication in the plot that the main cast are meant to be together which makes an implication in the nature vs. nurture debate which is inappropriate for Star Trek.