skp the video...read the article and you read that "R2 was attempting to score on the play" and at that time F5 is standing in the baseline. I can't tell if the ball was dead. The article also leads you to believe this might have been the 2nd collision at the plate. If so, awareness was already heightened.
In my opinion, catcher initiated contact as runner was sliding. Eject catcher. F5 escalated. Eject F5. R2 - well...eject him too because maybe he was continuing the play, but he certainly took advantage of the opportunity to inflict a little agony. It is tough to say how many people from the team that was at bat left the bench, but the team in the field lost about 2/3 of the team when they left the dugout.
I think the mutual forfeit was likely the only way to resolve it.