dancingalone
Grandmaster
If you watch the clip closely the guy in red did have his hands high enough to guard but the kick was placed directly in-between the two arms. Also because the guy in the red was kicking and leaning slightly back at the same time the angle made it impossible to guard. In this case hands up made no difference. All he could have hoped for was to deflect some of the power. And even that was a long shot due to the timing and angle of the kick.
Maybe you are right from a sport perspective. Outside of the ring in an altercation against someone you know favors kicking, I teach a more extended guard. The additional length allows you to anticipate and use your hands to help sidestep the attack, leading to a possible leg wrap or trap. It's the same idea why someone might try to use a jacket or other piece of clothing to help defend vs. a knife.