It's a very emotional reaction, as fan is just a shorthand for "fanatic." It is a highly emotion, reactive, state that comes with it a high level of expectations and a fear of change. If something changes then it might not still bring the same type of feelings.If all it takes to turn you away from a franchise you claim to love is one movie you didn't like, then I really have to question how much of a fan you really were in the first place.
That's what fanatic love can become-a desire for things to stay the same.
TLJ did something that Lucas had done before-dismantled the mythology. The Old Republic was not as great as Obi-Wan wistfully remembers. The Jedi Order wasn't perfect. It had flaws and scars and problems. Much like Star Wars films, the Jedi Order was intended for one thing, and became consumed by something else.
I get that different individuals react differently and ascribe more meaning that I do to Star Wars. I get that emotions run high and people react. To answer your questions @JD I don't think its a matter of questioning a fandom-I think its wanting it to stay the same-forever.