Rubber gun? No problem. Play with those all you want. However, this was not just a prop. It was a fully functional weapon that was supposed to be loaded only with blanks. By the way, you can kill yourself or someone with a blank - look up how Jon Erik Hexum and Brandon Lee died.
Regardless, that fully functional gun can be loaded with nothing, with blanks, or with real, deadly ammo. Nobody on a set should be playing with a gun that could potentially kill, any more than someone with a deer rifle or a handgun in their house should be playing with those even if they are certain the gun isnt loaded. Gun safety is practiced for a reason. Halyna Hutchins death was yet more proof that gun safety applies everywhere. It doesnt matter that the gun was only supposed to be loaded with blanks, or left unloaded. Obviously thats not how it worked out that day, and that day could've been any day. It wasnt make believe.
The only thing I agree with you here is that Baldwin shouldnt be prosecuted. He was relying on someone else to appropriately load the gun. But should he be sued into the ground? Absolutely. He wasnt just an actor - he was running the show. He had the responsibility to have a good crew that kept things safe. The armorers trial and discovery beforehand uncovered flagrant safety violations that were known by all. He couldve stopped the shooting, had her replaced by a responsible armorer, etc. After the violations on set, there should have been a safety review by a well respected pro. That wouldve been a delay, but it need not have been long. It doesnt take more than a day or two to check weapons and make sure there is no live ammo anywhere on set. It wouldve cost more, but cost control isnt a valid reason to get someone hurt or killed. Those bad decisions were on him.