Whether or not you believe what you’re calling “gun culture,” the fact that the gun in question is a revolver is one of the most relevant facts of the case.
A semi-automatic pistol, which is to say a single-hand firearm that is meant to be fired without being steadied against the user’s body where the ammunition is fed up the handle into to back of the barrel after each shot, until the magazine is exhausted, will not load the next round if you fire a blank. It relies on there being a bullet in the barrel to contain pressure long enough to push a mechanism that pops out the old bullet case and slides the next round into the chamber. In order for a semi-auto to use blanks, you have to modify it in such a way that you can no long fire live ammunition without destroying the gun.
Revolvers do not need such modification. Revolvers have a cylinder with boreholes running through it that form the chambers for the rounds. Pulling the trigger or cocking the hammer rotates the cylinder to the chamber, no pressure from the last round needed. This means that idiots on film sets can grab a revolver intended as a prop, put real live ammo in and target shoot in between takes and eventually mix up live and dummy ammo, causing people to be killed.