I really don't think the elbow was intentional. KG ALWAYS flails when someone grabs him, or he is wrapped up. He did the same thing here. I am sure he knew there was a good chance that he would hit richardson with his flailing elbow, but I am certainly not going to give him credit for doing it to defend his teammate.
From what I saw, KG said something to Richardson, turned his back on him, and then when Richardson came back at him, and the bench swarmed around him, he started trying to get himself out of there, flailing as he went.
So I am not going to chide him for being stupid, because I think he did the right thing, but I will also not give him credit for being some brave guy, standing up for his teammate, and putting Richardson in his place.