Legs are suuuuuper lethal. Hit the thigh, good chance of obliterating the femoral artery, gives you well less than a minute to stop the bleed before the person loses consciousness and maaaayyyybe a couple of minutes before they are unalived.

And as others have pointed out, they are massively under trained in the US, and the training they receive is basically that every person you interact with has a gun and they want to kill you, so pull your gun ASAP and make your first shot a kill.