It is a stupid argument anyway because they built the lead without him and were doing fine. Do you put him back out there up by 12 with 3 mins left in the half? What if he gets his third then? It would be considered one of the dumbest coaching decisions in finals history. The game had played out in such a way that they could afford to play it safe, until all of a sudden the lead was gone.
The lead evaporated because Hancock scored 12 points in 90 seconds (not because Siva took the game over). Once the lead was gone there was only a minute left - at that point, you'd be taking him out anyway, even if he had been in all along. Had that 14-3 run happened at the 6 minute mark, he'd have gone back in. But you can't do it in the last minute.