Mixon has never weighed 230 lbs. in his life, especially 2.5 years ago when this incident took place. He clearly doesn't weigh 230 in that video.
He did walk away. That is my point. But, when somebody comes after you with the intent to cause you physical harm when you try to walk away, you should not be obligated to let them cause you physical harm without diffusing the situation with your own return of being physical. He should only be allowed to hit her if his life is in danger? She could tase him, shoot him in the foot, and do numerous other very painful things without his life ever being in danger. Is he still not allowed to hit her to stop the threat of him causing more physical pain/injuries to him? Again, Rhonda Rousey weighs the same as that girl. She could cause some damage hitting a guy in the face. Is a guy who tries walking away not able to defend himself in that situation?
Also, her jaw was damaged from the fall on the table, not the punch.