This is a great point. I don't see why somebody should be able to steal my motorcycle- the object of my affection- and me being helpless. What's next, somebody kidnaps my girlfriend and I have to watch them take her away?
This is literally the case in many places that have laws about the "proportionality" of self defense. If the guy is much bigger/stronger than you, but unarmed, if you use a knife or gun to stop him you could go to jail. But as the saying goes, better judged by 12 than carried by 6.