I don't dispute that. But in most those 'other countries' literally anyone could be hiding a knife as easily as someone in US could be hiding a gun. So it appears in the vast majority of the cases where people are already right next to each other where both a knife or gun could kill someone, whether it is a knife or a gun is almost a moot point. It's only at a distance that you can treat a knife as a less lethal threat. Therefore the problem lies with the police, by vast majority.

The statistic isn't related to thrown weapons. It's how quickly you can close the space between you and your adversary, as well as how much bearing drift you can create as you do so.