It's absolutely relevant. Let's use a better example than that shitty can of soup one you came up with...
If someone built a house in the middle of the woods on unclaimed land, and built a garden in order to cultivate crops to eat, that would be something I would consider productive use of land. In your view, if someone else came along and took all the crops that the person spent his time and labor to grow, that any attempt to stop that guy from taking those crops would be the initial act of aggression. I on the other hand view the initial act of aggression to be the taking of the crops. Because the only reason why those crops are there for the taking is because the person spent his time and labor to grow them. He sure as hell wouldn't have grown those crops if he knew someone else was going to take them. I would consider that stealing though you seem to disagree.