Because nobody is paying attention to him or talking about him.

Like most everyone else in the NBA, he is an observer of the playoffs at this point. He's seeing LeBron, 'Sheed,  Booze, Deron, and Timmy getting talked about on Sportscenter every night. That used to be him. If there is anything that Kobe Bryant loves more than winning, it's being the center of attention (part of the reason Shaq is in Miami). So now we've got this man-child demanding a trade. I believe it's partly because he wants to play for a contender, but moreso because he wants people to pay attention to him and talk about him. Kobe needs his ego to be fed more than any superstar in basketball today. 

I expect this issue to cool off over the next week, once Kobe has been satisfied with the amount of media attention he has gotten. He'll be in a Laker uniform next season.