I call it "The Hollywood Flip" when somebody does that to a revolver.
A younger guy at the range almost did that to my favorite S&W revolver one time.
I told him that I'd pistol whip him with it if he did that to my gun. When I explained why, he learned something.
No offense to either of those 2 fellows, because I know they are highly regarded within the firearms community, but I think some of those "taboo's" are more relevant to custom or highly-tuned pistols rather than the factory-configured ones.
Using the slide release to send the slide home on an empty chamber? Happens all the time with most handgun users in the military, and outside in the civilian world. The "wear" from that is negligible compared to all the abuse those firearms take throughout training and general use. I think that is more relevant to 1911's than anything else.
Dry firing? Yeah okay, but again the custom-tuned handguns with lighter-than-factory triggers seem to have a lot more issues with that. If you dry-fire with your pistol day-after-day, I could see the potential for parts breaking. If you're doing it every now and then, I don't think it's a big deal, especially compared to regular usage/abuse.
I think a big takeaway from this video is that too much custom-work (like trigger tuning) can potentially start to compromise the firearm's overall reliability and durability. There is probably a good balance to be struck between lightening up a trigger and keeping it reliable for duty/protection uses. But if you're worried that your trigger is going to get ruined after a day of people dry firing it, I think the blame may lay more so with the trigger than it does with the operator.