Fair enough, don't play footie myself at any level, but I didn't see any shinpads at all on Nani and Carra didn't look like he dragged down his shin.
Not trying to look for excuses here and saying it's Nani's fault, just general curiosity.
That explains a lot.
I would expect someone like Nani who gets kicked bout most games to be wearing some kind of shin pad, it looks exactly like he went down his shin with the sheer force of the tackle.
I know you're not looking for excuses because there isn't any, the ball was long gone, it was a shocking tackle.