I HATE trash talking! I hate it! My players are not allowed to do it, I don't do it, and I do not understand it. I like to take care of business, and let what happens on the field talk.
Richard Sherman is wrong for the way he reacted. That is not how I want my players to win. If that's winning I'd rather lose.
However, when you put a microphone in someone's face seconds after playing a three hour violent game... you should expect such things to happen. Not every player can come down off their competitive high immediately, and can bring themselves back into the real world quickly.
Richard Sherman was wrong for what he said and the way he behaved, but if you put a microphone in front a player right after the heat of battle in professionals sports, you may just get more of what goes on on that field than you want.