I think it depends on the way you look at it. To me there's no difference between what Gutherson did and what Waqa Blake does every kick. Are all those people going up for kicks and swatting at the ball deemed a pass? For me a pass is when you're in control, what Gutho and many others do is bat the ball to give it momentum to carry on to the outside players.
I've never noticed before what refs call when they deem the ball to be propelled forward from that action so I can't use precedence in this instance.
It's still very frustrating that, if he thought it was a knock on (rightly or wrongly), he could see that Fergo was going to score as he didn't blow the whistle until he was 2m out from the line with no one in front of him. He could have let it play on, gone to the bunker and it would have been a try; this happens many other times where they think a foul has been committed. Like earlier in the game when he questioned whether the Brisbane kick chase was onside, he allowed play to continue Brisbane scored and he sent it up no try as he believed they were offside. Why in that instance did he not just call them offside straight away? Why in our instance did he call a knock on when he knows the bunker can rule on knock ons?