I can't grasp how anyone thinks this is anything but a cowardly sucker punch. This is no different than attacking an unsuspecting person from behind. In the handshake line, you generally can't see or at least don't have your eyes focused on anyone except the person in front out you. The guy who got punched had zero reaction time. #4 had a huge wind up and never would have hit him as cleanly if they had both been the first two in line walking towards each other. This situation was like the tall dude opening up a door and #4 being on the other side with his fist cocked. You can see #4 was walking tucked in behind the guy in front of him to get the best surprise. Unless he specifically told him that he was going to ruin him when they went to shake hands after the game, he's a skulking coward.
And sure, the tall dude probably said or did something that makes him an a$$hole too, but those were two pretty vicious blows. While it doesn't happen often, people die not that infrequently from getting knocked out (or fainting) and fall from standing. All it takes is a little skull fracture and subdural hematoma.