Here is the rule:
ARTICLE 7. BLINDSIDE BLOCK
It is a foul if a player initiates a block when his path is toward or parallel to his own end line and makes forcible contact to his opponent with his helmet, forearm, or shoulder.
Note: It is not a foul for a blindside block if the forcible contact occurs in “close-line play” prior to the ball leaving that area. The ball is not considered to have left that area if the player who takes the snap, either from a shotgun position or from under center, retreats in the pocket immediately or with a slight delay, and hands the ball to another player, or runs with the ball himself. This exception does not apply to any action other than a designed play. Any forcible contact in “close-line play” is still subject to the restrictions for crackback and peel back blocks.
Penalty: For a Blindside Block: Loss of 15 yards.
I rewatched the play several times and the Saints TE comes from the opposite side of the formation and is clearly moving towards his own goal line. The contact is initially helmet to helmet with the Saints TE initiating contact with his helmet first. You may not like the rule, but it was the right call according to the rulebook. If the Saints TE did not lead with his helmet, it probably would not have been called. Forget what Aikman and Buck said. They obviously did not know the rule.