"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."
Essentially Ropati took one step (maybe even less) back towards our end line and made forcible contact. You can't come back, like a peel back block which is what he did.
I don't like it either, but seems like they called the letter of the law.