It's a part of the prevalent "thug culture" today, kids aren't being taught by their parents as much as the media anymore and that means irresponsibility is king. Being dangerous makes you edgy and a kid with a gun is big dog on campus.

When my Dad was a kid, children brought their guns to school for show and tell but there weren't really school shootings to speak of because they were taught the ethics that go along with power, now that weapons are illegal, kids think it's cool.