oh look, it's another one of these threads.
Out of all the questionable fights recently (Silva/Bonnar - yes I realize it was to save a card, but it was still an awful matchup, JBJ/Sonnen, etc) this is one you should be least worried about.
Diaz lost a very close 3-2 round fight, for the interim belt. If the judges scored it 3-2 for Diaz it wouldn't have been the worst judging decision ever. Some thought Diaz won it, and he was riding an 11 fight win streak before that. I know I wanted to see this fight before everything went to hell last year, and many other fans did to. Yes, money/PPV sales probably is playing a small part in this, but it's not as if Diaz is some nobody the UFC just picked up off the street.
Hendricks/Kampmann was not for an interim belt, and never billed as a #1 contender fight. Hendricks barely squeaked by Koscheck, somebody who GSP dominated twice.
Hendricks and a lot of his fans assumed that if he won, he was guaranteed a title shot. I don't recall anyone ever stating that.