Yes, but that’s distinctly different from “violence looks cool.” One is a surrender to brute nihilism and the other is a fashion statement.
The Simpsons has touched on post modernism every now and then.
I guess we’re going to have to disagree. “Violence is cool” and “Violence looks cool” are pretty synonymous to me. And even if you don’t want to go back to the 70s, you can still trace it back to the 80s with James Cameron, Arnold, and the Die Hard/Lethal Weapon movies.
“What’s with all the eyeballs?”
“It’s po-mo! Post-modern? Weird for the sake of weird.”
“Violence is cool” has been a key element of human storytelling since Homer (no, not Simpson). It’s not post-modern - it’s pre-literate.
I don’t know about postmodern art, but if it’s carrying over concepts from postmodern philosophy then it’s pretty widespread.