I actually don't think that was a clean catch! The ball changes its arc.
I said that here on FR the day after that infamous play. I don't know how anyone can look at those photos and say with any certainty that the ball did not hit the ground.
Intially I thought it was a blown call but after examining the replay the ball has jumped up which is consistent with a bounce off the ground. The catcher blew it by not tagging even if he thought he caught it he should have known that the umpire couldn't know that for sure.