As years go by Bungie will be more well known for Destiny, and Halo will become more and more associated with 343i. Halo discussion will minimise over time, but it will never go away completely. Halo is part of Bungie's past, and not everyone has left the past behind yet.
But hopefully the threads about 343i will go away. Seriously.
The Universe Forum is for the discussion of Bungie created universes.
Halo 4 is a story that is based directly on the work of Bungie. So, people are going to discuss it, and nothing is at all wrong with that.
Discussion of 343 is probably borderline at best, but that can't be helped.
The point is, if you don't like discussion of Halo 4, either go to another forum or scroll past any Halo 4 threads.
Simple as that.