It was PI in the base explanation of the rule. But you call that kind of PI then you have to call a lot of things going on in that game (nothing borderline PI or D holding was being called especially in the second half). And what was going on in that game? Butler's play was SOP defense. You want to see some stretched jerseys (classic defensive holding)? Watch Atl's pass D throughout the SB. There isn't a Patriot WR whose jersey wasn't one size bigger after the game.
Then consider the borderline nature of the call yet it was instrumental in causing a second half, 4 point swing (that isn't called and it is fourth down - Atl kicks a FG). You don't throw that flag in a SB but whiners will look the other way on that.
Then take a look at the two late calls against the Falcons -- they were grossly blatant (compare Butler's and Atl Defender's PI calls - forgetaboutit). Further, that 4th quarter holding call on Atl that was a blatant, headlock, WWF take down, that play also contained a clear, extended, gross facemask not called on the same play (on Atl). Further, let's not forget the zebras also gave a valuable point to Atl based on a bad call (imagine if we don't convert the 2 point at the end? That stolen point would have been the difference).
No serious person is pointing to the zebras on the win/loss of this game. There were a few up and down calls but they let them play for the most part (the way it should be). Media blowhards that need clicks need to find some sort of tabloid splash to get clicks and this guys is a tabloid blowhard.