One possibility is that Silva just wanted (in some way) to piss off Dana White, which I'm sure HE DID!!! I think it's been documented before that White doesn't like when Silva "trolls" opponents the way he does since it shows he is not taking the fights seriously. And since Dana White WAS looking forward to promoting champion vs champion "superfights" like Silva/Jones and Silva/GSP, and Silva didn't seem interested (particularly with fighting Jones), he went into this fight trolling Wiedman so hard, he was GUARANTEED to piss off Dana White no matter the end result of the fight.
So with that said, and also considering the "relief" Silva seems to express in no longer holding the title, it seems that Silva really did win big here!