That's it in a nutshell. He didn't 'win the ball' - he 'touched the ball'. If he had gone in studs up, but foot down near the ground and therefore put his studs cleanly on the centre of the ball, it would have been an excellent tackle. By misjudging where the ball was going to be, all he's doing is endangering the other player.It's a bit UNLUCKY because he's rolled over the top of the ball and it's turned into a worse contact, but in turn that is because he didn't win much of the ball in the first place which his doing.
I'd be staggered if that's overturned. Touching the ball first is not enough.