i think people often think that movies are only told to tell a positive tale, somewhat defending or attempting to proliferate the message of the movie. lots of people end up detesting detestable endings, thinking that the movie is pushing that message
they completely miss that the whole point of the terrible ending is a lesson. sometimes lessons have bad endings
You're supposed to feel pity for almost everyone in the film.
(There's a difference in say, this film, and other "negative" films that people seem to cheer on.)