His rear foot moves towards the camera because he is adjusting the angle. His lead foot stays at the same distance. So he is not actually moving away from the opponent by any significant amount. So yes, you are nit-picking.
Both steps are moving away from the opponent.
The lead is stepping further away behind the guy.
The rear is withdrawing directly back toward the camera.
This opens space by at least a good foot or more.
It is not nitpicking if this is said to be stepping
into and smothering the opponent, when it's the exact opposite.
Note that Mazza is going slow enough that the opponent can take that small step back to recover his balance. At speed that wouldn't happen, and the opponent would remain off-balance with his body somewhat twisted. His right foot is forward and his right arm is stretched back and he is in the process of falling backwards.
Only if he's an action figure that can spin its body around independently, without the momentum being transferred to the legs.
The natural reaction of the human body is for the lead leg to be pulled back toward Mazza and for the torso to be turned to reface him.
In fact, this is what happens in the video/gif, and it would only be fuller if the guy responded and went with the force to take a deliberate step and counterpunch with his left, with added momentum from being pulled around.
Since the gif seems too complicated, let's look at some stills.
Mazza has flank. The guy's stance is almost parallel to Mazza's, and his shoulders are turned away. We can see the logo on his back.
Mazza steps away to the opponent's rear and pulls his arm which begins rotating his shoulders toward Mazza.
The opponent's lower body now begins to react to the pull, which is to follow in the same rotational direction as his torso.
Mazza has stepped back opening space. Opponent's stance has now opened up to face almost perpendicular to Mazza's, and his shoulders have come around.
For sake of the demo he remains unresponsive and doesn't turn with it with an idea to punch, which just makes him stagger a bit with his left foot.
If instead at this point the opponent went with the momentum and turned fully with a deliberate right step at Mazza, nothing would stop him from throwing a powerful rotational left punch straight to Mazza's face while he's already looking and committed low.
Its pretty hard to suddenly swing that rear hand around all the way to Mazza's new position on the blindside with any kind of effectiveness.
Usually, if he's flanked and refacing is barred, as he was and should have been kept, but not when his arm is pulled to rotate his front torso toward him when it was turned away.
The rear hand comes right around with it.
And, as I pointed out before....if he did Mazza is ready and able to deal with it easily. Because of the distance.
The distance actually makes it possible for the opponent's stance to turn back toward Mazza, from the flanked position it was in, plus Mazza not having a lead leg to block it the guy's stance from coming around.
Mazza actually helped him recover facing by opening up space and pulling him back around.
The punch would be swinging at his face at the same time he's pulling with one arm and punching low with the other.
It would be a miracle if he could "easily" deal with that by detecting the counter mid-attack, then abandoning the low punch he's already started to go cover high.
In conclusion, he had him in a good flanked position from the start. Why not keep him barred there and keep attacking to his core, affecting his balance from the flank?
Opening the opponent back up like this when you already "had him" is super risky.
This is not an attack on the whole lineage or method, but obviously, I would strongly advise against this technique.