When a fandom gets too big, it can develop its own set of weird rules and become toxic. All of a sudden you have people who all like the same thing judging each other over certain parts of that thing they like. Sometimes the fandom itself is obnoxious to people who are minding their own business, making it even harder to associate yourself with that thing you like. For a more fun look into fandom, here's a tumblr thread on how Darth Vader is the queen of drama.