Law doesn't care if you're an actor. It was a negligent discharge that resulted in death = manslaughter. Baldwin pointed and pulled the trigger = his fault.
The reason actors are an exception is that movie and TV studios agree in advance to transfer liability to a hired expert, i.e., the armorer/prop master, when actors are to handle real firearms. In fact, it's almost certainly in the actor's contract. So actors are only liable for
intentional crimes while on set, not accidents with firearms, since someone has been hired to make sure that doesn't happen.
