Because then Madrid would have no center backs for this match, thats the reason. I mean if RFEF have balls, they will clear the second Thiago yellow since it didn't touch Thiago's hand whereas Sergio Ramos' 2nd yellow was a straight red in itself.
Anyways, how can a Barca fan have the heart to call this donkey the next Puyol? He's inferior to Puyol in every department except playing dirty. He will never be like Puyol simply because he doesn't have Puyols character and mentality.