Because it was such a pathetic header, and Buffon was diving to save it, then clearly tried to readjust after it struck his hand and changed direction.
Have to say, I agree with Stroller. On the strict wording of the rules as expressed above, if the ball hits the hand in an act that is not deliberate, it is not a foul. I don't see how a ref can interpret the rule to give the opposite effect. Suppose the goal resulted from a Barca free kick - Neymar's in the wall with his arms at his side and the ball deflects off his elbow into the goal. Should that be disallowed?
Your right about Buffon strolls,i'm not sure he would have saved it, spot on re Vidal amazed he reached half time ran around kicking everything in a Barcelona shirt, i did think it was a penalty for the tug on Pogba,
