With a kitchen knife people can run away from the attacker and there'll be far fewer deaths than with an assault rifle. The damages are likely to be far less as than from being hit by a bullet from assault rifle where the heads of children literally explodes when hit, as was in the case of one of US daily mass shootings.
In USA it's illegal to possess hand grenades or Claymore mines, and a number of other explosive devices as well. And unlike assault weapons that are much harder to get access to.
It really is a dumb argument to compare a knife with an assault rifle (or machine gun, for that matter). A clear indication of someone that should not have access to weapons on the grounds of not know what damages guns can do.
A Lot of people can't run away. Some can't even walk away. Easy targets. Because of my knee, I can't run away (or walk quickly), so if some pinhead comes after me with a weapon that isn't a gun, they have a good chance of doing some damage if I don't know they're coming. Anyone in a wheelchair or using crutches/walker is screwed.
Using exploding heads as the rationale is wrong and it's only used as a spectacular example but it won't stop anyone who might, from repeating these horrible incidents since most of them didn't get the rifles illegally and they hardly care that children's heads are exploding. I suspect they didn't care whose heads exploded, as long as it happened. They do tend to be whack jobs, though. THAT's where it needs to change and only Congress can change that.
The gun culture is making people do stupid things. The online videos make their gloom and doom claims, people believe them and then, someone goes off and kills a bunch of people because the gullible are on the edge, anyway. Aside from making AR-style rifles hard/impossible to acquire, how would you stop the shooting incident in New Mexico, which was called 'random' by the sheriff? I'm pretty sure that kid would have used ANY gun if an AR wasn't available, but I haven't see anything about his life, family, etc or how he was able to have the guns and the AR wasn't the only gun he had with him.
They were banned in the '90s, they can be banned again, but at this point, I don't think the statistics will show much difference now- the last time, mass shootings dropped, but it was only 25%. While significant, we have more people who are exhibiting mental illness skirting the system and in some cases, they're altering Glock pistols with a 'switch' that makes it full-auto and using extended 30 round or drum magazines. But the last example tends to be used by gangs and drug dealing groups.
We have too many f&cked up people in this country and many aren't getting the treatment they need. They also needed their families to get to know them better and do something when they saw signs of trouble. There are other factors, like the Cleveland, TX case, where the shooter had been deported four times and he came back again- now, five people are dead because one of them wanted him to stop shooting his AR-style rifle IN HIS FRONT YARD.
The NRA has legal/tax problems and the organization is nearly bankrupt and I believe it's the fault of their leader. They could have been a good advocate and might have prevented a lot of this, but they just acted as an agitator.