Joubert was wrong, not just in the final penalty ruling. His yellow-card decision against Scotland wing Sean Maitland was also wrong. Maitland's grab at the ball seemed an attempted interception, not the deliberate knock-down Joubert ruled. Australia scored a try while he was off.
It doesn't matter Joubert couldn't go to the TMO on the last-minute penalty under rugby's protocols. There is little question he saw the replays on the big screen and did not reverse himself, as any referee can before play resumes.
He did exactly that in the Waratahs-Brumbies derby this year, yellow-carding Scott Fardy for a deliberate knockdown. The Waratahs protested as the replays were shown on the big screen - and Joubert reversed himself, sending the Brumbies' Fardy to the bin when he had originally ruled no punishment beyond a scrum to the Waratahs.
The real danger of all this is the clamour following Joubert's mistake. Be careful, because we may get exactly what we deserve after all the outrage.
Intriguingly, World Rugby put out a press release saying Joubert was wrong - something never before seen. The big question is their motivation. Some interpreted it as sacrificing Joubert, a view reinforced by the absence of one of the best refs in the world from the semifinals. Others felt that, by carefully outlining the error, World Rugby took some heat out of the issue. A sin confessed is halfway to redemption and all that...
There is another interpretation. World Rugby may be readying us for more TMO involvement, not less. That might be a nightmare. Mercifully, the tedium of TMO interference - England-Fiji took nearly two hours to complete, a scenario enjoyed by no one - has been reduced since the start.
But World Rugby, having seen the outcry over Scotland's unfair elimination, now have the perfect excuse to extend the TMO remit beyond foul play and try-scoring. They may feel the right decision is more important than another halt to the flow of the game. They risk the very essence of rugby, if so.
Some point to the NFL, their eight refereeing officials and multitudinous delays. American football is a stop-start affair which takes more than three hours to play, with the Wall Street Journal famously measuring the time the ball is in play at a paltry 11 minutes. It is nevertheless enormously popular. NFL involves four different offensive-defensive teams and a variety of set plays. It is a game of chess on legs - not intended to be an all-action sport.
Rugby is (even if it isn't, quite) and to allow TMOs more rein would be a large backwards step. Technology is here to stay, and so it should be, but it is a question of balance; knowing when to stop.
A TMO should not be able to halt a game and make everyone watch replays, unless a try has resulted from an error. Foul play can be noted and cited later if the referee has not seen the offence and ruled. The only exception might be if a player has been injured by foul play and has to leave the field, meaning the victim is punished but not the perpetrator.
Refs should ask only three basic questions of TMOs: "Try or no try?", "Any reason I can't award a try?", and "Can you replay what I suspect is foul play and give me your opinion?"
In addition to that, skippers of both sides should be allowed two captain's challenges per match, one of which can be applied only in the last 10 minutes. The game could be halted for such a challenge and replay but, once the two challenges are made, that's it - no more.
That would minimise injustices and delays. And press releases. But not necessarily controversy.