Of course coaches have stopped the game and grabbed the mic when fans are throwing stuff on the court disrupting the game, that's happened a bunch of times and it's obviously totally different. I've seen that several times, I've never seen a NBA coach stop a game to grab the mic and lecture his own fans about having class and to stop booing the opponent.
Popovich somehow made things even worse after the game when he said, "You don't poke the bear" and then got indignant when reporters asked if he could explain his comment a little further. So it wasn't about having class, it was about not fueling the opponent so he'll go off against you in the game.