Rule 8, Section 1, Article 3, Item 1 of the NFL Rule Book (page 51) states that 'if a player goes to the ground in the act of catching a pass (with or without contact with an opponent), he must maintain control of the ball after he touches the ground, whether in the field of play or in the end zone. If he loses control of the ball, and the ball touches the ground before he regains control, the pass is incomplete. If he regains control prior to the ball touching the ground, the pass is complete.
By this rule...it is a touchdown. Everyone all the way up to Goodell who says it is not is mistaken.
Control of the football was established until the reciever hit the groung (his feet). Further, he may have lost control of the ball momentarily, but he regained it prior to the ball touching the ground as he held the ball to his side...in control of it...until the tip of the ball hit the ground and knocked it out. The rule does not say he had to maintain the control after he was laying down...just until he touched the ground...which he did and if he lost control he had to regain it before the ball hit the ground...which he did.