Simple really, robots will do most physical jobs better than us and society needs to adapt to that. They will also be used in tasks we find disgusting like military conflict. Seeing how little real outrage drones deaths are causing; mostly because of deft political handling of the press; do you think employing robots against "other people" really is going to be much different?

The best outcome is that the onset of robots doing much of the work is that it frees enough of the world from economic strife to end the need for warfare.