I love this line and I think this is one of the most valuable things entertainment can provide. Great literature and movies make you feel some approximation of actually going through the thing that is being portrayed.
I've often thought that we (I'm American) get such a distorted view of violence from popular media. For every film that displays violence as chaotic, disorienting, and horrible, there are dozens of super hero type movies that display violence as utterly ordinary, necessary, and proper, where only the bad guys die forever and justice is ultimately served.
Additionally, so many stories end at "Happily Ever After" and neglect to communicate to readers or viewers that 99.9% of life happens in "Happily Ever After." Presumably "Happily Ever After" contains much less drama than the movie or book itself, but we never see it, so we are convinced that life can't happen at all, ever, without the drama that makes up the majority of the stories we are told.
Not just superhero movies - action movies, westerns, ancient myths and religions in which the heroes were always violent - maybe violent and cunning, but always violent, and the gods were often as ruthless and petty as nature itself.
Thinking of violence as anything but utterly ordinary, necessary and proper has been the exception rather than the rule in human societies. People still believe in war as a noble adventure that turns undisciplined boys into proper men... people still believe in holy war.
I think these stories reflect a fundamental need in people to fit a narrative onto a blind and arbitrary universe. We want there to be heroes and villains, for good to prosper and the wicked to be punished, for there to be a reason behind it all, even if that reason is aliens or the Illuminati, and a God who prepares a table before us in the presence of our enemies. We don't want to know that the world is capricious and arbitrary, that evil people die in their sleep surrounded by wealth and comfort while good people die in the street like dogs for no reason.
One thing to consider is that a lot of this is literally propaganda.
If you want war, you need rally public support. Or at least it is helpful.It is tripple helpful for young men to go there voluntary and see it as calling. You need then to believe certain things to facilitate building great army.
The army and war being shown as aspirationa was often political. Even censorship rules often facilitated that goal.
Most of the reason for that, of course, is marketing. Less violent movies can be rated to reach a wider audience. In the comics, depending on the era, writer, etc, superheroes could be extremely cynical and violent.
Another movie with a noteworthy use of subversion is The Thing -- you'd think something, anything will be explained by the end of the movie. Nope, nothing, more astoundingly, the end of the movie sets itself up as if it's preparing for a twist -- you don't even get to see the twist. You just know there is one, and the movie ends.
Because its explained in its entirety at the beginning: "Se til helvete og komme dere vekk. Det er ikke en bikkje, det er en slags ting. Det imiterer en bikkje, det er ikke virkelig. Kom dere vekk, idioter!" ~= "Get the hell away. It's not a dog, it's some kind of thing. It imitates a dog, it's not real. Get away, idiots!"
A nitpick however: "American Psycho" is not really a serial killer movie, is it? In fact, it's debatable whether any killing occurs at all. (Of course, the embarrassing sequel completely misses the point, from what I've read -- and I refuse to watch it).
I was really emotionally affected after that one. Good fun.