So you genuinely didn't see your victim come in on the right side of the screen and take a swing at someone's head? He then walked away. The friends of the people he hit chased after him and beat him up, which is the bit you showed.
And clearly you haven't seen this part before so you actually had no idea whatsoever as to whether the bit you showed was unprovoked or not and just said it was because it fit your narrative.
Large amounts of unconscious bias at loose on this thread.