1. Due to the popularity of the heroes, everyone has an idea of what Batman and Superman are “supposed” to be like, thus making many people disappointed, unlike with Guardians. It is also the third cinematic Superman and sixth Batman, so it had to live up to their standards.
2. Controversial casting
3. The mixed reactions to Man of Steel
4. A month after Deadpool, a month before Civil War
5. Generally shit on by the media, including over-exaggerating the negative responses and saying stuff like it failed ^^
6. Coming after years of MCU movies, which have made people think there is only one way to make a superhero movie (A serious superhero movie? What??? They have to be self-mocking because superheroes are for NERDS)
7. Mass confusion due to it coming only four years after Nolan’s Batman Trilogy
8. A three-year wait that made many people lose interest.
9. An attempt to start a franchise eight years after Marvel did.
If you’re going to talk about money, then be accurate.