"Jerome did not have a perfect match – no referee in a World Cup final ever has – but England's fans should be questioning their own scrum rather than the officials," Kaplan wrote in a column for the Telegraph.
"Clearly the scrum was decisive in this match, but Jerome was simply rewarding the dominant team. It is rare to see such superiority in one facet of the game at this level but it was clear from early on that the Springboks were far more powerful at the set piece."
Kaplan, a South African, said Garces could have even South Africa with a sixth scrum penalty, "but for the fact that they made good ground while he was playing advantage".
"Having analysed each of those decisions I do not think one of them was incorrect. Four were unquestionably right, one is difficult to judge as it happened on the far side from the television cameras, and another could possibly have been a reset but is not a clear and obvious error."
England were dominated all game by the Springboks' scrum, going on the back foot early after tighthead prop Kyle Sinckler was concussed in the third minute.
Kaplan, a test referee between 1996 and 2013, said England had "slightly more cause for complaint" in other areas of the match, but also benefited in other areas.
"A couple of breakdown decisions [against England] were questionable … On the flip side, the advantage Jerome gave England in the first half is one of the longest I have ever seen and it clearly went on far too long."
Overall, Kaplan believed Garces "handled the occasion well in his last match as a professional referee".