ARTICLE 3. No player shall target and make forcible contact against an opponent with the crown of his helmet. This foul requires that there be at least one indicator of targeting (See Note 1 below). When in question, it is a foul. (Rule 9-6) (A.R. 9-1-3-I)

I think this one is ruled out because it wasn't a hit with the crown of the helmet. Some in other threads keep ending there, it appears. "No crown. No foul." However, it doesn't end there.

ARTICLE 4 No player shall target and make forcible contact to the head or neck area of a defenseless opponent with the helmet, forearm, hand, fist, elbow or shoulder This foul requires that there be at least one indicator of targeting (See Note 1 below) When in question, it is a foul (Rules 2-27-14 and 9-6).

This one requires two things: 1) defenseless player and 2) and "indicator".

Note 1: "Targeting" means that a player takes aim at an opponent for purposes of attacking with forcible contact that goes beyond making a legal tackle or a legal block or playing the ball. Some indicators of targeting include but are not limited to:

• Launch-a player leaving his feet to attack an opponent by an upward and forward thrust of the body to make forcible contact in the head or neck area
• A crouch followed by an upward and forward thrust to attack with forcible contact at the head or neck area, even though one or both feet are still on the ground
• Leading with helmet, shoulder, forearm, fist, hand or elbow to attack with forcible contact at the head or neck area
• Lowering the head before attacking by initiating forcible contact with the crown of the helmet

Note 2: Defenseless player (Rule 2-27-14). When in question, a player is defenseless. Examples of defenseless players include but are not limited to:

• A player in the act of or just after throwing a pass.
• A receiver attempting to catch a forward pass or in position to receive a backward pass, or one who has completed a catch and has not had time to protect himself or has not clearly become a ball carrier.
• A kicker in the act of or just after kicking a ball, or during the kick or the return. 
  A kick returner attempting to catch or recover a kick, or one who has completed a catch or recovery and has not had time to protect himself or has not clearly become a ball carrier.
• A player on the ground.
• A player obviously out of the play.
• A player who receives a blind-side block.
• A ball carrier already in the grasp of an opponent and whose forward progress has been stopped.
• A quarterback any time after a change of possession
• A ball carrier who has obviously given himself up and is sliding feet first.

I think most of the comments I've seen point to face masks being the initial point of contact, which I read as an indicator, and it being a defenseless player that just caught a forward pass and hasn't had time yet to defend himself.

Others argue "no crown"; but, again, that's a separate set of tests. Crown isn't required under the second set of tests.

In the end, the thing that to me says it 100% should have been called is that there is very strong debate, so to me the overarching rule should have been enforced:

When in question, it is a foul.

When in question, a player is defenseless. 

Unless the refs can eliminate all doubt and explain why it ISN'T targeting, it should be called. I can only assume they would say he wasn't defenseless, since I can't see how they argue out of forcible contact to head or neck. Maybe refs should be required to lay out why something was or wasn't targeting when they make the announcement.