The arms master on the set loaded the firearm for the shoot. It was handed to an assistant director who didn't bother to check the status of the firearm and assumed it was a 'cold gun' that is not loaded with any sort of live ammunition. The assistant director handed it to Baldwin and told him it was a 'cold gun.' Baldwin didn't bother to check the status of the gun either.
Gardner is right. Hidden in that statement should have been the final red flag, but it was ignored. The assistant director should not be handing the gun to an actor, and should not be saying if the gun is loaded or not. It must be an armorer handing the gun off. No one should be handling the gun, but the armorers and under very limited circumstances the actors.
The solution is not having other people do the armorer's job. That clearly leads to untrained people doing the job. The solution is for the armorer to do her job.
I will blame Baldwin for one thing. When he saw the assistant director hand him the gun, he should have said stop everything, why didn't the armorer hand me the gun. As an old actor, he knew how sets worked well enough to know that assistant directors are different from armorers.
The problem here is you are looking for actors to be firearm safety experts. Not only are they not, we do not want them to even try. They will just mess up. Nor are assistant directors firearm safety experts. Again, they will mess up. What next, are you going to argue that Baldwin should have been a doctor, and provided medical treatment. It would be better if Baldwin gets out of the way, and allows real medical staff to provide treatment.
You would have a stronger argument if you argued Baldwin should have realized that the safety process was not being followed. Rather than claiming to be a firearm safety expert, Baldwin should have realized he was not handed a gun by a firearm safety expert...
The problem is that is not a criminal negligent mistake, so no crime.