Yes, but fighting is a contest that involves a lot more than simply getting hit in the head. There is even the option to barely ever get hit in the head. The KO is not the most frequent way of winning. And you never just stand there and brace for a man to wind up and hit you his absolute hardest, with the express goal of hurting your brain. You have defense.
Here, idiots just stand up in one spot and let a guy throw his hardest possible strike at them. There is no ducking and weaving, ducking under for a take down.... your brain gets no rest. If you somehow survive the first slap, you have 60 seconds before the next one. By the third slap, even if you didn't go unconscious, you may have taken as much brain trauma as in a 15 minute fight, depending on fight style.
Fighting is an art where brain trauma MAY NOT come into the equation (of course, it often does). Slap "fighting" is a contest, but not an art, where brain trauma IS the ENTIRE equation.