Newton gets hit all the time after throwing the ball outside the pocket. Only players like Brady get calls for those plays.
i'm over the play, but I think it's the driving into the ground that is the problem and as far as I could tell, those rules are still supposed to extend beyond the pocket. but apparently they don't. but I think they will going foreward. If you happened to watch any Carolina and Atlanta you saw a how it should be done when Peppers chased Ryan out of the pocket. He threw the ball, Peppers continued his momentum. He didn't have to put the brakes on to avoid contact. he got his contact, but instead of wrapping him up and driving a guy into the ground because he knew he wasn't tackling a ball carrier, just as Barr did, he just made the contact he's allowed and put his arms out. Like most other people do in that same situation.
I have no problem with allowing contact out there. I'm not always a fan of the QB protections because they can take such advantage of it, like Flacco last week. IMO if you want to use the slide, you should have to initiate it at least 3-4 yards before any defender gets within that radius or the protection is gone. But I also think picking up a QB and driving him into the ground when you know he's not a ball carrier just taking a shot to take a shot. I can see the case for one not being able to avoid contact, but what Barr specifically did afterwards, was all a conscious decision to drive a non ball carrying player into the ground. I think plays like that are going to be looked at this offseason. But then I thought that was already written in the rules, so what do I know?