I understand the point it's trying to make (that the difference between a fool and a brave person is whether they succeed in their stupid action), but its not entirely correct as foolishness and bravery aren't mutually exclusive, but more importantly bravery isn't as much of a virtue as courage.
Using a bullet's breadth and war as an example, a fool would charge a machine gun nest thinking they wouldn't get shot, a brave person would charge a machine gun nest not even considering the fact that they could get shot (which is also foolish), but a courageous person would charge a machine gun nest in full knowledge of and fearful of the fact they could get shot, but choosing to do so anyway because they've decided that the outcome of their action (i.e. disabling the machine gun) is more important to the cause than their own individual safety, which while virtuous, could also be foolish depending on the situation (e.g. a infantryman courageously charging a machine gun nest when their side has a tank a few minutes away).