Faceguarding is no longer a penalty... as long as there is no contact.
Here's the deal with that whole penalty/no penalty:
When Hitchens touched Pettigrew, the ball was still in Stafford's hand... which would have made the penalty illegal contact. However, that was not what was called on the field, the referee that threw the flag signaled "pass interference". Pass interference is called when there is contact WHILE THE BALL IS IN THE AIR... Hitchens, while he was faceguarding (which is legal) never touched Pettigrew. So by the rule, there was no pass interference, and they rightfully picked up the flag. So you ask: "what about the contact?". The "illegal contact" was never called on the field, so the referees were unable to enforce it post hoc.
It's the same deal with plays that are reviewed... in the process of a review, should the referee see a penalty that was not called or not called correctly, there is nothing that can be done about it.
For all the people complaining about the call, the referees were absolutely correct in picking up the flag for a pass interference penalty (because there was none), and the penalty for the the illegal contact (wich should have been called, but wasn't), it falls into the same realm as all of the other bad/missed calls that happen in virtually every game.