This girl, like her or not, made herself into a celebrity by the power of gossip, media, and money. This managed to get her a TV show, an album and a lot more money and fame.
David Letterman made himself into a respectable TV persona by being sort of rude and harsh on his guests, this approach made the show very long running, successful and economically satisfing, for him and the TV channel he works for.
Personally, I don't find it sad or funny, I don't care about the lives of those people at all, and so if she's being humiliated or taking part in this joke - I don't really care.
The both win, both on the fame angle and the money angle. The one who looses from this is the audience who get to waste time, money and brain cells on celebrities...