Why is anger the only emotion that is not viewed as a good thing a movie(or any form of media) should try to trigger in an audience. There are plenty of movies endings that aim to leave the audience feeling happy, excited, sad, confused, horrified or even disgusted and people praise those movies for striking those emotions.
Because Hitler gave it a bad vibe.
>>85162517
Because people get over other emotions
A movie leaving you happy will only do so the first couple of viewings
A movie leaving you angry will leave you angry about it forever until it turns into apathy which is the worst thing you can shoot for