It's not racking the slide , it is letting it slam home on an empty chamber that is not good for it. Without stripping a round & chambering to slow the momentum, the slide slams home under full force of the recoil spring. This will cause wear, peening and eventually breakage of the associated parts of the slide, barrel, barrel lugs, link and slide stop shaft.
And with the title of "Grand Master Know it all" you shouldn't need to ask this !![]()