Why are you quoting 15.7 (d)?
At 15 seconds into the clip there is clearly 2 players on their feet in physical contact over the ball on the ground so we have a ruck. Law 15 has nothing to do with the situation here. It is law 16 that we must deal with.
Here the halfback is digging for the ball and is not part of the ruck. He must not be touched until the ball is out of the ruck. Here the ball is not out of the ruck and he is tackled.
Does anyone think that a halfback who is not part of the ruck is fair game to be tackled when he is in the process of freeing the ball from a ruck?
I (gulp) agreed with the Aussie commentators. I thought it was just a tackle with no ruck formed.
Blue 10 was the first Argentinian player there and went straight off his feet (onto his knees with his left hand supporting him on the ground) and sealed off the ball (PK right there). He was definitely off his feet
before Blue 12 touched him, so no ruck can form (ruck formation requires a minimum of one player from each team BOTH on their feet).
While its still a tackle, Blue 9 arrives and Gold 12 immediately shoves him away. Thats a clean out in my book, and therefore in accordance with 15.7 (d)
IMO, the YC was not warranted, in fact the PK should have gone the other way for Blue 10 off his feet and sealing off.