The notoriously conniving leader of The Vale was desperately trying to worm his way into the affections of Sansa Stark by driving a wedge between her and her sister Arya.
So she goes to Bran, and Bran tells her everything she needs to know, and she’s like, “Oh, s—.””
To say that the Game of Thrones season 7 finale was packed with intense action and dramatic revelations would be an understatement of dragon-sized proportions.
Furthermore, the final cut of the sequence did enough to indicate that it was Bran who revealed the truth to Sansa, rendering the removed scene unnecessary.