I don't agree with making the UNR a live ball foul. If you're calling that action a foul, it's because his progress was already stopped, so this needs to be a dead ball foul in my opinion. And on top of that, I just don't see this as flagrant. I don't think it's any worse than a typical late hit.
Having had a sequence somewhat similar to this just a few weeks ago, I think you're getting a little picky here. If that was the only thing that happened, then maybe we discuss it and come out with an agreement, but several things went down and they had to put them all in order. Your point is, at best, arguable rather than obvious so given everything they had to sort out, even if it was a mistake it was very minor. I personally think it could go either way and would leave it up to the ones on the field -- who blew the whistles and made the ruling as to when the play was dead -- to decide.
In this case, I wouldn't be surprised if 93 had been a problem child and that stunt was the last straw. Would I toss him on the first play of the game for that? Maybe not, but I would take whatever reasonable action necessary to keep the game from getting out of control. This was reasonable.
Matt should have said "declined" rather than cancelled but it communicated to everyone what happened, so I wouldn't call it a "poor announcement." Fans don't know the difference. A little like calling Team A for being offsides instead of encroachment. They still fouled and it is still 5 yards.