The person holding the firearm is ALWAYS 100% responsible for the damage done with that firearm.
You can spin it anyway you like; but being an actor, being stupid, being irresponsible, being a jerk, being an asshole, being Alec Baldwin, being any of these things does not remove you from the responsibility of handling and checking a firearm for safety at any time.
Alec Baldwin is one of the VERY VISIBLE point men for the GUN CONTROL LOBBY, you would think that someone in that position would be very aware of the lethal nature of a piece of equipment that was specifically designed to DESTROY A TARGET!
I do agree with you, in theory. Sounds right. But in the world of movie productions, the armorer has that responsibility.
I think we BOTH agree that NO PROP GUN should ever double as a live-fire gun used for target practice during breaks.