So, clearly FIFA is cracking down on the video because, yeah, it’s easy to criticize that call. Because it’s weak.
However, one thing is clear. It’s a slide tackle from behind. Which, in order to be clean, there needs to be 0 contact. Rough contact from behind... red card. Any clear takedown is a red card from behind. That’s what they call a “dangerous play” even if the result isn’t an injury or even a standard foul. The intention is to discourage slide tackles from behind.
In this particular case, the Aussie defender clearly takes a slide tackle from behind, gets ball, and the offender makes contact.
It’s a foul for sure. And it’s an unfortunate one because it’s in the box. Pretty much the shittiest combination of rules. Slide tackle from behind, even though he got ball first, in the box. Penalty kick. Flaws of the game revealed.