Zach Snyder made Superman into a completely unvirtuous, unheroic monster with no regard for human life, because Zach Snyder is such an overgrown child that the idea of a hero with godlike powers who actually refrains from using them in order to protect those weaker than himself from the fallout is too mature a concept for him.

James Gunn made Superman into a whiny, inept beta simp who is constantly being upstaged by his girlfriend, his dog, his enemies, less powerful superheroes than himself and even the people he's supposed to be protecting, whose every moment of character development is undermined by a jokes, and who commands no respect from anybody despite having the power to crack the world in half if he wants to. Because James Gunn is such an overgrown child that he can't even take seriously the idea of a hero with godlike powers who has respect for and commands respect from people less powerful than himself.

The surface-level take is that Hollywood simply can't allow the comic-book Superman to exist because he is the embodiment of the idea of masculine heroism that they've dedicated themselves to undermining and destroying. But really, I think they just can't understand him because they're all children. The kind of perpetual teenagers who are so self-absorbed that the selfless virtue of traditional masculinity seems simplistic and infantile to them, and who either refuse to take it seriously (Gunn) or who, like Snyder, take themselves so seriously that they mistake teenaged cynicism for adult wisdom, adolescent narcissism for adult confidence, and the childish desire to be taken seriously by adults for actual maturity.

Superman seems childishly silly to guys like that because they never grew up.