I think you have a point. Let's face it, there are millions of people surviving around the world in war-zones and peace-zones and they don't need karate, Ju-Jitsu or anything else.
Hell... I bet they don't even need your secret. Guess that makes a lot of us like them. I'm sure we'll all survive without you.
Maybe the reason the powers that be tried to stop your instructor was because he was teaching people like you such a deadly secret.
Perhaps the reason people treat you like cr@p
is because you start treating them in the same way.