Vaderisnothayden said:
The common understanding of canon in fiction (the understanding you're citing) is based on the mistaken view that the "creator" or owner always puts out genuine stuff or knows best what's the real thing. The idea at the core of the idea of canon is what's the real thing. That's what's at the heart of it. People have just gotten used to accepting that the word of the "creator" is the best guide to what's the real thing. But it isn't.

In its core essence the idea of canon (and thus the meaning of the word canon) is about what's the real thing. But you won't get the real thing if you go by a bad guide like the judgement of a "creator" who's lost touch with the work. Defining canon is all about defining what's the real thing. All this stuff about the offical line and canon being stuff created or accepted by the creator is about looking for the real thing. People are effectively just figuring that the offical line and stuff created by or accepted by the creator IS the real thing. But it isn't always.

Say what you like, but you are redefining clearly defined words, and thus destroying their usefulness for communication.

The word "canon" has many meanings, but when used in the context of fiction, it has been used to mean what I explained it to mean in my previous post.