Superman often paired up with his friend, Batman. When they were together they always fought criminals, but the two heroes were always the main characters in these stories. The villains were merely staffage, necessary but uninteresting dime-a-dozen badguys that had to be there to get the story going. But the whole point of the plot was to give us readers the chance to admire our splendid heroes.
As time went by, Batman in particular became darker. When drawn by Frank Miller, Batman's "persona" and appearance became hard to separate from that of a villain. During the era of Curt Swan, the readers had been asked to idolize their comic book superheroes because the heroes were so good. Now, during the age of Frank Miller, the message was rather that the villains were so horrible that the superheroes, particularly Batman, had to become a bit evil themselves in order to prevail over their awful adversaries.
These days, the villains are often just as important as the heroes. In modern superhero comics and movies, one of the most important goals seems to be to create villains whose sheer evilness is as unspeakable as possible.
John Lennon sang about being a working class hero: "A working class hero is something to be".
These day the lyrics may be changed slightly: "A supervillain hero is something to be".
James Holmes, who carried out the massacre near Denver, seems to have said he was the Joker.
What is the significance of someone like James Holmes? Perhaps nothing. There is always going to be a few crazy people in the world, that's for sure.
But the world we live in these days sure feels different from the world I grew up in, in the 1960s.