I found the whole thing interesting. The video is clear and Wayne Barnes correctly calls that it was a deliberate action. He also asks the TMO to confirm he agrees and that we are looking at a Yellow card. I'm sure the TMO's have similar code to the 'let me repeat what I have seen' from a AR, if they think the sanction is wrong.
On a Saturday had I seen that in one of my games I would have issued a RC for the following reason, its a deliberate actiion of foul play and while not always the case the position of the player unable to defend himself and the riskk to the player of injury also would convince me further that its red.
Ben