Here is how I interpret this video.

A1 is in a physical scrum with B1 in front of him. From behind and to the side, R1 come in and puts his hands on A1. A1 is basically reacting to this contact/physical touching by pushing away as if to say, "get your hands off me," not knowing its an official. Hence why I was taught to avoid touching players or getting in a melee.

I'm not saying it's right to touch an official. I'm saying it was more instinctual and he may not have known it to be an official......although that whistle was blowing a lot!