It was flagrant to me. The ref appears to have talked to them early in the match at the center. When the kid got to his feet at the end he nails his opponent in the back of the head, and then continued to pound on him as they went out of bounds. He was slugging him or trying to at that point and had lost his composure. That all happened pretty fast right at the end. Match over isn't the wrong call. Hitting your opponent like that is by rule flagrant.

Could it be called unnecessary roughness or unsportsmanlike? Sure. That would have been the "safe" call to avoid being criticized for making a big call in a big match. The ref could have sent each wrestler to his coach, had a little visit with each, and restarted.

The kids leg was obviously messed up and he wasn't hardly able to hobble around on it. At one point it looks like it gives out and he's falls to the mat. Hope he heals up.