He mentions the dramatic increase in damage from rifle bullets traveling at 2500+ fps. People often mention this without understanding the reason. The speed of sound in water is about 4500fps. The shearing effect of pressure waves generated by the impact of a bullet are amplified by constructive addition of reflected waves, as the speed of the bullet at impact approaches the speed of sound in water, the the shearing force doubles and even trebles (waves are reflected from more than one direction - You can demonstrate this in a bathtub full of water)... The result is a disproportionately large quantity of macerated tissue.
He also makes the bad assumption that 40 and 45 are slow. You can hit 1100fps with a 180-200gr bullet in either caliber. 10mm will get you beyond 357 performance (not entirely true - You can push a 170gr bullet at 1300fps from a strong 357 handgun with a 6 inch barrel).
I think he's mainly talking about factory ammo though,not someone who likes pushing the limits. Probably because in relationship to the number of people with guns for self defense there's probably not a very high percentage that reload or know about pressure and ballistics and things like that. That's my guess anyway.
Yeah, factory ammo is pretty poopy. I've been shooting a bunch of 45 factory recently, and the more I shoot, the more I miss my own loads. But the factory saved me some time that I spent casting a bunch of 44 for silhouette matches.
I will admit, however, that factory 45 lobs into a target at 100m very repeatably. But a full case load of Unique is a whole other ballgame