The Columbine guys watched violent movies, listened to heavy metal or punk or something, and played violent video games. Do you think all those things weren't brought up as contributing to their behaviour?
Yeah, but that's just usual bullshit American media looking for a scapegoat. Just like all those folks out to get Judas Priest and Ozzy Osbourne for subliminal messages.
The Columbine guys were outcasts -- and the stereotype is that outcasts do tend to flock towards an "alternative" life style which involves metal, horror, comics, fantasy, video games, etc.
Basically, they were a couple of nerdy geeks that snapped after years and years of incessant bullying which no teacher gave a shit about or ever said anything. They went out with a mission to kill as many jocks as they could.
This South Korean guy was supposedly "dumped by his girlfirend". I'll bet you $100 this chick got drunk, had a one night stand with this guy, he took that to mean she loved him, they woke up in the morning, she ran away, never returned his calls, he got a gun,
maybe listened to some Ozzy and Priest, played a little Res Evil, watched Cannibal Holocaust on Nates old region 0 DVD, and THEN went nuts.
But seriously, there was definitely some chick involvement, no doubt.