This is why that arguments holds out! They do not have duty to anyone else because of this. And I'm okay with that as long as the stockholders are punished (no silly slap on the wrist style punishments) for crimes of their PtLds, as then the owners will force toe PtLds to have serious ethical standards.
This is why I think the argument that a corporation only has a duty to it's stockholders is rank bullshit.