Those holds happen every play. The refs pick and choose when they want to throw a flag
I mean you can say the same about a lot of things in football.
They call PIs when the ball is thrown 10 yards over the receivers head. Nobody knows what a catch is anymore.
But is weird to complain about a call when it was the right call. It is one thing to complain about a block in the back when it was clearly a clean block, but this one looked bad live and on replay. If you get beat on the edge and you hook the guys neck it is more surprising when they don't call it. I remember two plays where KC and Pitt got away with PI but they were both borderline but I don't feel like the refs influenced the outcome of the game.
Worst call I have seen in a long time is still the fumble on Borks forward pass. I just don't understand how anyone could have called that a fumble when the ball came out of his hands and went forward into the dirt like 10+ yards.