He also said, correctly, that he doesn’t know everything.
He was dead wrong in saying the umpire made the wrong call because he does not know about the comment in the rule (quoted in a post above) that specifically addresses this situation.
If you want, you can complain that the comment should have an exception for a situation in which the ball gets past the catcher before the batter hits him with the bat. But, where would you draw the line on that?
In this case the ball squirted behind the catcher and whether or not the runner on third could score would depend on how well the runner recognized where the ball was, how fast he is, how quickly the catcher recovers the ball, and whether the pitcher comes in to cover the plate.