Right or wrong? The correct decision, but a clear break of protocol to get there. Referee only asks - "Is this a try Yes or No."
The TMO can only comment on whether the action of the try being scored was legal and cannot comment on the actions before the act of scoring the try unless the referee had asked "Is there any reason why I cannot award the try"
In this case the TMO overstepped his authority and asked, "Do you need any other information before the goal line." The TMO may not comment unless directly asked about events before the goal line.
Whilst Johann Meuwesen's comments on the act before the try was scored should not have been used by the referee at the end of the day the try was correctly not awarded as the pass was forward.