There are, as I see it, at least four distinct reasons why this is an unusual circumstance that warrants mention: 
 *Miller has been awarded the highest honors possible within his profession, the Vezina and the MVP of the Olympics. Normally when you get profanity used by one player against another, it's from, how shall I say, rather more marginal players. 
 *Miller specifically stuck around till the end of the game to air his grievances to the media, despite suffering a concussion. 
 *It ties into the larger issue of Lucic in particular and then Bruins in general (cf. Chara-Pacioretty) having a reputation for thuggery. 
 *It's rare for such damning words to be spoken to media regarding another player. Normally there's at least a pretense of civility. Miller did preface his harshest words with a qualifier ("I respected him for how hard he played") but then slammed him unequivocally ("Gutless piece of shit").