I don’t really see anyone pleading for their “ideas” to be canon.
You must have missed the first sentence in my post. I stated that the idea of “canon” at all is stupid in the first place. There is no need to make a distinction between personal canon, or franchise canon, or any canon. One is free to interpret a story however he or she sees fit.
Official canon is useful to keep continuity between different installments of a franchise. When watching Enpire, knowing that the events of Star Wars “really” happened certainly helps to understand the movie.