It almost sounds to me like... you approach original fiction from a more idealized objective state (or on some level you think it's...better? to do so? less limited), while your appreciation of fanfiction is generally a much more subjective thing, just from the language and vocabulary that you're using.

I'm still puzzled as to where you find this (my words, obviously) sense of "obligation" to "the writers" comes from, that somehow you're "failing" them, (and/or your expectations of yourself), leading to the mild guilt. Can you expand on that at all? And how, in your view, does this failing of them tie into the way you see other readers allow their view of canon to be distorted by what they read?