Not convinced about that YC, thought it was pretty much accidental & would've been let go had the injury not occurred & the injured player not subsequently been landed on.
I initially thought the same but on the replays I think this is very much something that falls into foul play territory. It would have been worse if he wasn't about 80kg wringing wet.
He grabs hold of the Australian player high up around the shoulders then rolls over to the side and pulls down with his body weight coming down on the Australian player's leg.
It had elements of both a croc roll and a hip drop tackle in the way his body weight came down on the Australian's players lower leg.
It shouldn't matter that it was accidental. It's a technique that has a high degree of danger.