God, it's like encountering the Prequel Trilogy bashing crap. You show something challenging and ambiguous, and people act as if the world is falling apart. No wonder people seemed to prefer their entertainment more bland and conformist.
That, or you have some of the usual suspects (certain MCU fans) who cannot wrap their minds around the idea that superhero movies can be larger than life and serious, instead of the Transformers/stand-up tributes which make up too many MCU films. Its no surprise some of this kind of fan cannot stand the best films of the MCU--the Captain America movies--because they're not in the 90s comic/cartoon tradition seen in the Avengers and Guardians movies.