In my commercial experience with the merchant navy, there should be no special protection for merchant ships unless it has been determined that the activity in which they were involved was definitely in support of the armed forces.
I cited one case in the U.K., which is the only one I have come across, where this happened. The descendants of the sailors who were lost when the ship was sunk made an appeal to the courts, and they were successful in their appeal.
In the commercial world, though, when a merchant ship is sunk or goes ashore or is abandoned—provided the ship is declared a constructive total loss, the insurance companies and cargo owners have been paid off, and the owner doesn't want anything to do with it—that ship is up for grabs for anybody.