“I strongly suspect this guy punched some of the officers during the arrest...”
If I was being beaten and tasered to death by 6 cops, I think I might take a swing at them.
I wasn’t there and the current video is pretty poor, but knowing the job as I do, the deceased probably took the swing when he was being searched or was about to be handcuffed. If he connected,(and it appears that he did at least to one) well, not condoning the level they took it to, but if someone punched you, what would your immediate response be? Furthermore, if they punched someone you considered like a brother, would you not respond in kind?