I think Tony oversold it, but I liked the call. That play should be a flagrant every time.
Many smart people have pointed out that whether or not injury results is a terrible way to determine if a foul is flagrant or not because there are too many pieces of randomness that go into an injury, and unintentional fouls can cause terrible injury, clean plays can cause injury (look at that recent hockey play), and dirty plays can have no injury. So, regardless of the injury outcome, you should call flagrants on intent.
And in this case, TA had a clear open layup, and Ginobili had zero chance to make a basketball play, which would either be a play on the ball or positioning to take a charge. He tried neither, instead aiming clearly for only arm. Additionally, he clearly swiped downward with his follow through, which was the decision by him that made the play have incredibly dangerous potential.