It really is rude to point your chopsticks at someone while eating in Japan.  I've been guilty of doing it, by mistake of course. The "ninja chopstick defense" isn't real but I have a feeling that if you pointed your chopstick at a ninja, you would get slapped!  Looks like J has a little bit more patience for foolishness than your average ninja.  I wonder if Ryan will back down a little now...probably not.