You've beat me to it BR. Where I watched the game last night, you couldn't hear the commentary so I missed what McRae said, but that was to be my comment on the matter. You can accidentally kick the ball forward at a play the ball, knock it a yard backwards from a high kick, and yet it will almost certainly be deemed a knock on. I can accept benefit of the doubt, if it looks like a try but you can't be 100% certain, but this wasn't even close.
As a sport, we led the way with using technology in situations like this, and then we have some muppet confounding everybody watching by ignoring the evidence available to him.
Maybe it's time to employ three video referees and let them have a mini jury. Granted it may take a few seconds longer, but it's worth trying if it will eradicate farcical decisions like the Roby "try".