I think that the point is being bigger and stronger is going to win a fight most of time. Of course if you are Rickson Gracie who dedicated his entire life to fighting you don't have to be big and strong to win fights but the point still stands. Furthermore, nobody in a civilized society should be carrying the burden of worrying about ninjas coming out the shadows to beat you up all day long. If you were truly worried about your safety you would lift weights and be strong.