Why are we celebrating the release of a criminal?
In Martha's case, I think it may be that many feel that the punishment did not fit the crime in the first place. The "media attention" serves as a means of protest for what seems to many to be an unfair sentence.
With respect to your general assertion that the news has been diluted due to the need to entertain, I fully agree. I remember the days of the 15 minute news cast with John Cameron Swazy (not sure of spelling). Then there was the "Good Night, David" and "Good night, Chet" era. I miss the days when Walter would end with, "And that's the way it is." Yes, once there was the real news, and there were tabloids for entertainment. The line has become blurred. As a society, we have been overly influenced by the media. Our moral pitch is tuned more by Opra and Hannity and Colmes than the collective wisdom of the ages. "Do unto others as you would have them do unto you" has been replaced by "If it can be bought or sold, it is good."