A semi automatic pistols, other than a few gas operated exceptions, work on the physical principles of kinetic recoil energy from the fired round to operate the slide action of the gun.
When the pistol is fired the recoil energy is used up in the movement of the gun, its parts and everything attached to the gun including the shooter. There is a required amount of resistance to movement by the frame to allow the slide action to work. If the shooter allows too much movement of the frame, commonly by relaxing the wrist of the gun holding hand (limp wristing) the pistols action will not cycle properly. The shooters hand movement uses up too much of the recoil energy essentially stealing it from the slide.
The problem is more common in light framed pistols or when shooting low powered ammo.
It is a real phenomenon. I have a friend that has a real problem jamming pistols due to his relaxed grip. We where at the range once and he was shooting his Norinco 213 9mm Tokarev. He'd jam 2 or 3 rounds of every magazine. I ran 4 magazines of ammo through it and couldn't get it to jam once but hand it back and he'd have it jammed on the second shot. He managed to Jam my Beretta 92, my Glock 19, my Sig 220, all of which I've put many thousands of rounds through with never a jam. He does fine with a full size 1911 or a 7.62 Tokarev. but the 1911's a heavy framed pistol and the 7.62 Tok is a hot round. After some coaching and a bit of chiding regarding limp wristing and holding the gun tighter, his problems cleared up.