The technique is also easier the weaker the recoil spring. Which means on average the less powerful the caliber the easier it will be to rack the slide one handed.
The 10mm Glocks for example are going to be more challenging than the 9mm ones like used in the video. And a .380ACP gun with large enough sights is going to be even easier.
I have yet to attempt this with a handgun that the strength of the recoil spring really affected the degree of difficulty in any material or even perceivable way. As a reference point I have done this with at least 20+ different pistols ranging from .380 up to 45 ACP.
Not the best skill to practice much. Damaging the sights, throwing them off, damaging clothing or belts, and with many techniques pointing a muzzle at yourself or a random direction to do it fast is just not ideal.
I have never seen sights damaged. I have heard of it happening. However, any decent sights should live up to more than an adequate amount of practice just fine. Sure fragile target sights or cheapo sights of some sort might be vulnerable, but they do not belong on a fighting gun, which is the type of weapon this manipulation is relevant for. I have guns I have done this countless times with and they are no worse for wear. At pistol courses they regularly do this. As I said I have heard of rare instances of sights breaking. IMHO those rare occasions simply identified faulty equipment. If this broke, damaged, or misaligned sights you would hear about it, since this is done a lot at shooting schools all over the country as a matter of course.
If for some reason you were too worried to use your sights you could use the ejection port. That is what I use on my LCP anyways as it does not have sights that will work for one handed manipulations.
If this is damaging your belt, buy a real gun belt (you should have one anyways), or use the edge of your holster/mag pouch.
Doing it while standing with your belt in a known fixed position when prepared is also a lot easier. Actually having to do it with a bullet in your other arm, while wrestling or off balance, or laying on the ground, won't be as clean and pretty.
This is pretty much true of all defensive handgunning skills. If your point is to argue against it as a viable solution for empty chamber carrying I agree. If your point is simply the truism that a one handed malfunction drill is going to be more difficult at time when the chips are down and you really have to use one hand than during training, duh, of course that's true. That is hardly an argument against training the skill. The same thing can be said about any defensive handgunning skill, even things like drawing and shooting. Training cannot simulate every aspect of reality, that is not a reason to forego training.
As to pointing the gun at your self or in a random direction. Do the technique right and you don't do either of those things. It is like saying don't every practice drawing your gun because pointing a gun at yourself or in random directions is unsafe. However, in both instances proper technique avoids the concerns entirely.
Which then gets into even more dangerous technique like using a limb or part of your body to push the slide back.
I limb or body part would be way down the list of things to use. Holster, belt, mag pouch, heal of my shoe, the edge of my pocket knife, etc would all be things I would use first.
I don't mean to sound rude, but what training in defensive handgun shooting do you have? These critiques seem to be based in ignorance about how to perform the techniques and how they work.
Once again useful skill, but not one that can safely be advised to practice.
That is nonsense. Why then does every knowledgeable handgun instructor and shooting school teach the technique? You really think if it wasn't safe it would be drilled repeatedly at front site, thunder Ranch, Costa Ludas, Haley Strategic, gun site, Magpul Dynamics, etc, etc, etc, etc?