In no way was that a shot at Rondo but was probably more of a shot at Melo and the Knicks. The Celtics play more together and don't play hero ball and at the end of the game Paul, who typically has the ball in ISO is not afraid to pass the ball if he doesn't have a good shot and it's usually to ray or KG.
Melo however played hero ball and look where it got him, a lose. He should have passed that ball to Douglas, who had just hit a 3 before, or someone else who was open. He did not take advantage of the C's double team and he just tossed it up. That is the reason why I do not think the Knicks will win a title until Melo and the rest learn true team basketball.