Here's a bit of news from Toronto that might help put this in perspective. On June 2, 2012 a gang member opened fire on another gang member in the food court of the Toronto Eaton Centre. The intended target was killed but so was a nearby shopper. Three others were wounded. On July 15, 2012 two or three rival gang members decided to have a gunfight at a barbecue in a Toronto suburb. One of them was wounded. Two innocent bystanders were killed and 22 others were wounded [Scarborough shootings: What really happened on Danzig?].
Imagine what the death toll in Aurora might have been with more than one person blasting away with an automatic weapon.
All civilized nations have strict gun control laws. Their citizens have this strange notion that killing other people is never a viable option and they can't imagine why anyone would deliberately buy guns with the intention of shooting a fellow citizen, even in self defense or prevention of a presumed crime.
I guess some nations have a long history of solving problem with gun violence and it's difficult to abandon that option.
Image Credits: Charlton Heston (top), Tombstone (bottom)