Brutal doesn't even cover it...but, its baseball.
There some talk that the catcher blocking the baseline as the reason for the call, but that looks like bullshit too.
MLB Official Baseball Rules "7.06", and "Rule 2.00 (Obstruction)."
7.06 says: The catcher, without the ball in his possession, has no right to block the pathway of the runner attempting to score. The base line belongs to the runner and the catcher should be there only when he is fielding a ball or when he already has the ball in his hand.
Rule 2.00 (Obstruction): If a fielder is about to receive a thrown ball and if the ball is in flight directly toward and near enough to the fielder so he must occupy his position to receive the ball he may be considered “in the act of fielding a ball.” It is entirely up to the judgment of the umpire as to whether a fielder is in the act of fielding a ball.