Snyder is the one who made everything super serious and grimdark, which everyone hated.
That was his call and he defended it with crap like saying a real dark movie would be Batman getting raped in prison.
Heck let's just do some greatest hits of dumb things Zack Snyder said, showing that he was completely the wrong person to handle a DCEU or touch Batman/Superman.
"I feel like [Superman fans] were taking it personally that I was trying to grow up their character." — In reference to MOS/BvS and the neck snap specifically
"If you know the true canon, you know that I didn't change Superman."
"In some ways, [Batman V Superman] will be, I hope at it's really best, the impossible version of Watchmen."
"He just didn't fit the tone of our world. I'm very strict about what goes into this universe down to all the details." — on why they didn't use the TV Flash.
"What we've done is create a place where they can really be the mythological characters as designed in the comic books. If you're a fan of them in the comic books, you'll get a great opportunity to see what they look like, and how they move, [that] they're real."
"I really wanted to show the violence is real, people get killed or get hurt, and it's not fun or funny. I wanted a hero in Superman that was a real hero."
"In the Frank Miller comic book that I reference, he kills all the time."
"Everyone says that about " Batman Begins." "Batman's dark." I'm like, "Okay, no, Batman's cool." He gets to go to a Tibetan monastery and be trained by ninjas. Okay? I want to do that. But he doesn't, like, get raped in prison. That could happen in my movie. If you want to talk about dark, that's how that would go."