The non-call that ended the Panthers' win over the Patriots was a bad call. Not a historically terrible one, in a vacuum: worse missed penalties and more egregious undeserved flags happen every week in the NFL. But on the last play of the game, a supremely entertaining slugfest between two Super Bowl contenders, players and viewers deserved better than a judgment call that rewarded Luke Kuechly for mauling Rob Gronkowski.
Let's start by accepting that the officiating crew was on top of the rulebook. The flag on Kuechly, quickly picked up, was for defensive pass interference, and not the lesser fouls of illegal contact or defensive holding. This is very much an important distinction, because only a DPI call requires the ball to be catchable. Had one of the latter two been called, the ball's proximity to Gronkowski—or lack thereof—wouldn't have mattered, and the Patriots would have had one more shot. But as excellently broken down here, pass interference is the only penalty that could have been called correctly, since the ball was in the air when the contact occurred.
Let's go further, and stipulate that the referees were quite clear—eventually—about why the flag was picked up. Here's referee Clete Blakeman, walking two pool reporters through the play:
The back judge saw that there was contact and the defender was not playing the ball and that led him to throw for defensive pass inference, was the initial call.
There were two officials that came in. One was the umpire and the other one was our side judge and there was a discussion at that point as to the, in essence, the catchability of the ball due to its location. So it was determined at that point in time that when the primary contact occurred on the tight end that the ball, in essence, was coming in underthrown and in essence it was immediate at that point intercepted at the front end of the end zone. So there was a determination that, in essence, uncatchability, that the ball was intercepted at or about the same time the primary contact against the receiver occurred.
The back judge saw the contact between Kuechly and Gronkowski, and threw his flag. He wasn't paying attention to Tom Brady's release—that's not his job—or to the flight of the ball. Two other officials came in and overruled him, declaring that the ball couldn't and wouldn't have been caught anyway, and that was that.
So. The entire controversy hinges on a hypothetical. Had Kuechly not draped himself over Gronkowski, would Gronk have had a shot at the ball?
It's close. The more I look at it, the more I think Gronkowski was trying to set his feet to come back to the ball, which by Brady's admission was underthrown, but was put off-balance by contact from Kuechly. I'm confident enough to make three statements: 1) That flag isn't picked up if this wasn't the last play of the game; 2) That flag isn't picked up if this game was played in New England; 3) Blakeman severely fucked up by not explaining on the field why there was no penalty.