Yes, that is true. But you have to remember this isn't a sports league, the UFC doesn't always put on fights between the best. They put on fights based on what SELLS ( Kimbo, Brock Lesnar, James Toney ).
Anderson Silva vs Vitor is a HUGE, BLOCKBUSTER fight. One of the best strikers and probably the FASTEST mma striker against the undefeated middleweight champion. That is a HUGE, HUGE $$$$$$$$$$$$$$$$$$$$$$$$$$$$$ fight.
That's what counts at the end for Zuffa.
And personally, I'd rather see Vitor vs Anderson rather than Anderson vs anyone else in 185, even if they are more qualified / have beaten more 185 guys. It's just a near Shogun/Machida-esque level of epicness. JDS/Cain is also on that level of epicness. Vitor may be the ONLY 185 guy that can embarass the shit out of Anderson Silva striking wise. He must be there mentally, though.
Ah, what a great time it is to be an MMA fan.