I find it ironic that Coppola could praise Black Panther after Ryan Cooglar screened it early for him and then pivot to calling the whole genre "despicable" and lacking enlightenment, knowledge, and inspiration. It's also ironic that directors like Coppola and Scorsese are taking shots at genre filmmaking when they came from a generation of filmmakers that did genre filmmaking that previously wasn't taken serious as "art" and showed that it could bring with it both critical and commercial success. You would think that directors that were a part of the shift and that history in cinema and had to deal with the previous generation dismissing their subject matter that they would understand better.
It mostly sounds like elitist gatekeeping trying to keep Marvel specifically out of the conversation of genre films that changed the industry since they don't feel they should deserve the credit that comes with that.
On a related note, while obviously this comes from superhero and specifically Marvel's incredible run of box office success that creates bitterness and resentment in the changing industry since it begins to represent that change, whether it deserves it or not, I've always thought the emphasis of blame on the superhero genre and blockbusters was misplaced since we've had the blockbuster tentpole films holding up the industry for decades now and they were arguably filled with more empty entertainment than what we currently get consistently with the MCU. I think there is more blame to be placed on Hollywood's risk-adverse betting on franchises, adaptations, remakes, and reboots, which the superhero genre is certainly a part of, but that extends beyond blockbusters to even just lower budget comedies and other genres. The goal of the studios greenlighting them isn't to make art, but to reliably make money and a time when the industry is struggling to find ways to keep people actually going to the theater at all.