Because the attacker is not going to be fair. Take a look at the video:
The problem with man-to-man polite talks is that they do not work if one of the parties is not interested in talking but aggression. Asshole’s attitude was obvious and trying to calm him down or reason with him was for nought. And Asshole misdirected the gentleman’s attention to execute his attack with success. There is bodily harm inflicted, make no mistake.
Create distance, have barriers in between, lock doors, leave the area, call police.
Self defense is not a sporting event.