Well, because canon is frustrating seen as "but why is the dashing hero evil? and why have I been robbed of The Adventures of Sith Lessa in favor of focusing on him?" and provokes affectionate eyerolls seen as raw material for fanac, but is amazing seen as "ooh, the fact that they have such a stark division between good and evil because of the fact that their politics repeatedly devolve into the pro-world-saving faction and the literal anti-world-saving faction allows a tradition-obsessed entitled nobleman who abuses and uses in his personal life to do a lot of good even though in any other work he'd be a villain" or "hey, what if canon is actually propaganda that Benden had the harpers put out?" or such things.

Also you keep giving me fic ideas.

And you point out the rare places where canon makes more sense than I gave it credit for.