Taumoepeau was given a yellow card for the first-half incident last Sunday, but it wasn't upgraded to red, apparently because of Ritchie's slight duck into the tackle.
The captain subsequently failed a head injury assessment, which means a mandatory 12-day rest.
Many observers thought the upright hit merited a clear red card and the bunker review — where officials have eight minutes to change their initial decision — should clearly have seen that.
But Gilpin said mitigation, such as the height of the tackle, comes into it and defended the system.
"The foul play review officer in the bunker is obviously seeing more angles than television viewers at home or people in the stadium are seeing, and we think there is great consistency there and the bunker is working well," Gilpin said on Wednesday at the tournament organisers' weekly review.
"The strive for consistency and understanding is ongoing as a sport, and as a complex sport with a collision area. Hopefully, what everyone is seeing is there is clearer communication now on field and therefore more broadly about the decision being made in the bunker, as it comes back to the referee."
From the start, however, the tournament generated much debate about the inconsistency of match officials giving cards for head contact, after World Rugby said player welfare was its top priority.
England flanker Tom Curry was handed a three-game ban after his sending-off for a dangerous tackle against Argentina when his yellow card was upgraded by a bunker review.
But no action was taken against South Africa centre Jesse Kriel for his head-on-head collision with former Wallaby Jack Dempsey in the victory against Scotland. The incident was missed by the referee and Television Match Official.
Plus, Chile captain Martin Sigren was guilty of a similar tackle to Curry's during the loss against Japan - but he got a yellow card.
