Guns, Guns, Guns!

If you, like me, drove your own vehicle to school when you could drive, you'll remember the parking lot on the North side of the gymnasium, (featured prominently in the 1965 yearbook).
Guys who drove pickup trucks frequently had gun racks behind the truck seats, with a rifle and shotgun hung on those racks. I'd bet some of those guys never felt a need to even lock their trucks.

We never felt threatened by the guns. We never even felt threatened enough to fear leaving our cars and trucks unlocked.
Today, when a gun appears on a TV or movie, you hear the "evil" music played to indicate how we should feel about the threat they pose.
What has changed in our society/culture since 1965?