Guns deliver damage and death more efficiently than an edged weapon (I agree). But, edged weapon attacks are still far more prevalent than gun attacks. It's a matter of availability. Everyone says guns are more accessible than ever before because there are more guns, which is true. Not nearly as much as an edged weapon. That's why when we're trained as police officers to respond to a deadly threat force, you treat someone with a knife just like you would a gun because in the end, you can end up just as dead. They teach us the Fairbairn's Timetable of Death in knife defense, which is a far more hands on and requires MUCH more repetition than gun offense. The difference between something like 6 weeks of hands on knife/hands defense compared to two weeks of gun DEFENSE and four weeks of gun OFFENSE.
http://en.wikipedia.org/wiki/William_E._Fairbairn
Chart developed from his teachings:
The average sport knife sold in the U.S. (I say Sport Knife but I mean any crappy Gerber you can pick up at Wal-Mart) has an average blade length of 3 inches. Only one of the spots identified on the chart is more than 3 inches (The heart is 3 1/2 inches but i'm saying thrusting power if you're aiming for the spot, you'll at least nick it) and it's the stomach. The target areas might not seem that big but look at the areas that get cut the most during a knife encounter (arms). Easy to bleed out and die from a small shallow wound on those areas.
Knife attacks are generally much more dangerous because 99% of the time, they are spontaneous. They happen well within your average reaction zone (4-6 feet generally). It's a quick flick of the wrist or thumb on spring-loaded models of stabbing instruments and if the person knows what they're doing, they're on you and the knife is in you before you can blink. Reaction is always slower than action. Of course, training can help and being wary is always a good thing but just because you didn't die from a knife attack, does it make it any less dangerous/gruesome/damaging to your mind? Some of those kids in China will be scarred and maimed for life. Some of them will probably never recover from the injuries inflicted upon them. I would rather die than to suffer an excruciating life of agony and pain from a near-mortal wound inflicted upon me that debilitates or permanently scars me and then the emotional trauma?
And yes I agree, it's far more likely someone will defend themselves against a knife than a gun. People associate gun with danger because that's how it's portrayed and (rightfully so) it's something you should run away from. But not a knife because people haven't been taught that knives or edged weapons are just as dangerous as a gun. Whatever might have instilled this line of thinking weather it be gun violence is more hyped, or maybe knives are just an everyday part of our daily lives that we don't think that the kitchen knife we pick up to cut our sandwiches could someday be used to kill us, I don't know.
All I know is regardless of how you feel about guns, don't discredit the maniacal and brutal aspect of the human psyche. While a gun attack is a very efficient, methodical, and brutal way of killing people, it takes a far greater amount of "bat shit insane" to go up to a person (especially a child) and stab that person with a knife. It takes a level of crazy far beyond the most talented and brutal gun touting psycho to get up close and personal with another human being (ESPECIALLY a child) and maim, stab, cut off something, make less beautiful, or kill someone with a knife. Ask anyone who's been in a firefight and ask them how fucked up they were after killing someone with a gun. It'll be far less than when you had to ram a knife in to someones temple or dig a blade up their ribcage to sever all the internal organs in the upper torso.