I disagree with this sentiment. I watched my sister's DII soccer team play in the National tournament this past year. They forgot to show up for the first 10 minutes or so, allowed a goal on like the first shot, and then had to play their ###### off for the rest of the game. They lost 2-1 in OT.
10-15 minutes after a game is not enough time to compose one's self. The initial loss adrenaline from the game and the realization that it's over is just kicking in about 10 - 15 minutes after the game is over. There wasn't a single dry eye on their side of the field as they were being handed the second place "medal". It's devastating, and frankly, I think it's perfectly ok to show your emotion after you just lost the single most important game of possibly your entire career. For 3 of those girls on my sister's team, that was the last competitive soccer game they will EVER play.
I'm not saying ball your eyes out and make a seen, but to shed some tears, hell I have no problem with it.
I do agree that they only played 55mins and should not have celebrated, but still.