There is no "hand ball" rule per se, rather, Law 12 states that is illegal if a player "handles the ball deliberately (except for the goalkeeper within his own penalty area)". This means that is not a foul if the ball touches a player’s hand, only if the player intentionally handles the ball. Therefore, all of those times that a defender kicks the ball right into a player’s hand or the ball bounces up and hits an arm, these are not fouls and should not be called.