He literally talks about how hip movement results in head movement. Seriously man, you're being ridiculously obtuse about this. You're acting like I made some absurd claim when all I'm saying is that movement at the hips will move the head. 5 seconds in front of a mirror will prove this. Shifting weight moves your head, flexing at the hips moves your head, and both are necessary for proper punching technique, which will thus move the head. Watch any good puncher.
Where the fuck do you get off thinking this isn't coming from firsthand experience? You keep saying shit about me lacking perspective or experience but the reason I'm not receptive is because, as I already told you, I've felt the punches of many different styles and been taught those punches as well, and none compared to the boxers. Not the TKD guys (they had probably the worst punches), not the kung fu guys, not the karate guys, not the kickboxers or nak muay or sambo guys, not the MMA guys, nobody punches as hard, fast and with as much leverage as boxers. They have the best, most refined punching mechanics of anyone in the world. I've tried punching the way I was taught in other arts and by other stylists and it's always been worse than boxing punches. On the other hand, every time I show someone who doesn't box how to punch correctly they're amazed at how much less effort it takes to hit with more power. And that comes down to simply weight transfer, rotation and leverage.
It had power because Kimbo absolutely smashed his own head into the punch:
Look at how his head comes forward with his chin straight up. Also, yes the kick does land on his leg. You can very, very clearly see it make contact on his knee and push his lead leg back, so Kimbo ends up with his head WAY out in front of his feet and falls down. Note that he wasn't ko'd by that shot, he catches himself on all fours. It was the followup shots that TKO'd him when he rolled to half. You're the one who doesn't understand where the power is coming from here.
Hard to beat Joe Louis or Mike Tyson for proper power punches:
Notice how both of their heads move because they sit down on the opposite hip for leverage as their body rotates, and how both the guys they hit go down looking like they just got shot. That's how to throw a damn punch. Keeping the head centered is both less stable and less powerful. It's simply inferior, which is why TKD guys punch like shit.