You're reading too much into it IMO. I think deep down he doesn't fancy Anderson's chances in the rematch and figures he'd like a crack at that belt himself. He has better TDD and a base than Anderson and a striking style to give Weidman fits, so I think he may be right in thinking he matches up better against Weidman (though I still think or hope Weidman would find a sub eventually if the fight happened).
Even if Anderson wins, it is very unlikely he will retain the belt for all 8 of his remaining fights (Weidman I and II will count as the first two fights on the 10 fight contract already), at age 39 and well into his 40s by then. Sooner or later Anderson will lose again, and if all goes according to Machida's plan then by that time he should have built an impressive case at MW for a title shot at whoever displaces Anderson, whether it's Weidman again or someone else.
Machida has done all he can at LHW and part of it has to do with a size disadvantage against guys like Jones and Davis, he was always more of a MW and now with Anderson looking to be out of the picture one way or another he can do what is best for him.
What I don't think is going to happen is Anderson retiring prematurely with 8 fights left on his contract. Remember that the UFC owns your entire fight life until you fulfill that contract ... after retirement Anderson would not be able to box Roy Jones, compete in ADCC, endorse or start another fight promotion, or even put an exhibition fight with freaking Jungle Fight if he was so inclined, until he fought and fulfilled ALL of those fights or the UFC let it go (unlikely, seeing how greedy and possessive they are). He would have nothing to do but play Playstation and eat burger king all day long.
I don't think he'd like retirement with that ball and chain weighing him down, taking away his options. I think he'd rather fulfill the fights, maybe take some easy or fun fights against other aging legends and so on before he actually retires. Sort of like Fedor did with Rizzo and Monson.