Ultimately, the decision did not have a major bearing on the result with Sanzaar suggesting de Allende instead deserved a yellow card.
In those circumstances, with five minutes remaining, there is essentially no difference between a red and yellow card.
That doesn't alter the fact Garces made a big mistake - and had it been earlier in the enthralling test, the Boks would have been hugely disadvantaged by the error.
At international level referees are encouraged to own TMO decisions involving foul play.
In this instance, Garces used the big screen to make a decision with little input from English TMO Rowan Kitt.
In doing so, the responsibility for getting it wrong largely rests with Garces.
He saw something most did not.
He clearly believed de Allende's forearm made immediate, direct, forceful contact with Sopoaga's head, rather than sliding up off his chest with no malice as it did.
While Sanzaar's transparency around de Allende's discipline process should be applauded, the same does not apply to referees.
Don't expect to hear anything about what, if anything, now happens to Garces.
If he faces some form of review, no-one will mention it publicly.
This is not a one-off, either.
World Rugby was more than happy to publicly voice its frustrations after Sonny Bill Williams won the right on appeal to have the All Blacks' game of three halves included in his month-long suspension after the British and Irish Lions tour.
But the governing body is still curiously silent over the major influence Garces had as assistant referee on fellow French whistler Romain Poite and the match-deciding blunder at the end of the third Lions test at Eden Park.
Such a lack of transparency around a major event is galling.
If World Rugby feels the decision was right, say so.
Ditto if it was wrong.
Ironically, the penalty which saw the All Blacks draw level at 3-3 against the Boks last week was eerily similar to the one Garces and Poite conspired to botch so badly in July.
And yet three months on, we are still none the wiser over the outcome of a review involving either Frenchman - or if there even was a review at all.
Professional players are held to account through selection every week.
Coaching jobs are, similarly, on the line each season.
But the lack of transparency around referees' performances gives the impression they are not treated in the same manner. This is not true - but how would you know?
Dialogue is held regularly between coaches and referees both pre and post-match.
Coaches often send officials clips to detail issues they had with decisions, and referees often admit fault in this forum.
They are never going to get everything right.
Boks coach Allister Coetzee may, for example, send Garces footage of Scott Barrett charging into a ruck with no arms and say the incident warranted further sanction.
Referees are much like players in that they are prone to human error and endure peaks and troughs in form.
Sometimes they are taken off certain matches to avoid conflict, or demoted, but these decisions are never made public.
How hard would it be for Garces to put his hand up and talk about his mistake?
That approach would command respect and knock the issue on the head.
The counter argument to public accountability around referees is the focus is always on the negative.
Rugby is already difficult enough to interpret without adding further pressure.
And let's be honest, referees are virtually never praised for a good display.
The other issue is a plethora of top referees ready and waiting to step into the breach does not exist.
Drop one, and the next in line could be worse and less experienced.
New Zealand has just seven full-time refs.
Still, a little transparency goes a long way.
On the field, we trust referees to control every aspect of a match.
Off it, they are hidden away and protected.
