Here is what a poster from another MMA forum has to say regarding this matter. IMHO, he is comparable to onepunchJD, judom, daemondragon, and Jack Slack at UG. Take it for what it's worth, but he has a track record of outstanding posts with regards to the nuances of MMA. And no, he is not a GSP hater. In fact, he has long maintained that GSP has fought the toughest competition in the history of UFC.
"I don't buy into GSP's rhetoric about him believing that Diaz is the #1 contender. He has always been a fairly level headed guy, an able commentator and analyst of the sport, a fair judge of his division and others. He must know very well, as we all do, that Hendricks is the guy who should be getting the shot. A guy coming from a loss, and not having fought in quite some time, being lower ranked than Hendricks cannot be reasonably said to be the #1 contender. I also don't think he still holds on to the grudge with Nick and that he desires to fight him above all things. And I don't think it's money that's speaking either.
So why ask for this fight? The Silva vs. GSP fight was, more than ever, on everyone's radar. Anderson had explicitly said he wanted it next, White said he wanted it and was going to try to make it. Silva shows up at the Condit fight, and says he wants to set it up. Clearly, in spite of the fanbase being divided as to whether Jones vs. Silva was a better fan, this was a fight that was drawing all the hype it was expected from it.
GSP was getting a lot of heat, given his fairly obvious reluctance to take the fight. Hendricks, for all his virtues, is not a particularly popular guy, nor do many believe he has much of a shot against Pierre. But Nick is obviously a star, and a fight with GSP would have the fans hyping it up. This is true even if the odds are still heavily on Pierre's favor, and if Hendricks is generally considered to be more deserving. Diaz is more popular, and more people would be excited for that fight, nevermind fairness.
Had GSP taken on Hendricks instead of Silva, the disappointment of not seeing the Silva fight materialize would have been quite steep. GSP would have drawn a lot of criticism for ducking, warranted or not. But a fight with Nick creates the sort of hype and pleases the many fans that wanted it to begin with. It's a great way to say no to the Silva fight, and not have to assimilate the bulk of criticism.
So I do think that GSP took the Diaz fight primarily as a way to dodge accusations, and to divert the public's attention from the fact that, well, he was explicitly backing down from the Silva fight. Just my two cents."