I will never understand being so angry at a fictional work to a point that you feel justified in threatening and harassing the people who are part of it... And also their relative and loved ones!
Amazing but more usual that one might think, it's the same anger you can see in people that identity themselves with some other fictions like religion, nationalism, football teams, ideology, race, etc. When watching a movie you kind of temporarily turn off your disbelief to experience joy, sadness, anxiety etc but when the movie is over the healthy behavior is the recognition that everything was an acting. But with the fictions that I just described somehow the disbelief is never turned on, the critical thinking is canceled.