Scorsese has made comments in recent years about his dislike for the MCU/comic book movies as has Francis Ford Coppola and others. The director of Dune basically said it was copy paste. But I feel Scorsese's recent comments about how filmmakers need to fight back to "save cinema" that basically CBM's are toxic for cinema I think is a little much. It spits in the face of CBM fans like myself. It's fine to not enjoy it but to say CBM's need to go away isn't right.
Related but tangential, I am a little surprised that Quentin Tarantino is kind of indifferent/aloof to the MCU considering that he used to work in a comic book store years before becoming a filmmaker.