The only thing I can think of is that the Right-wing extremists that support this guy don't care what he used to believe, they care what he says he'll believe in the future. They are not afraid of being betrayed by what Mitt used to believe, they are interested in what positions they can pressure him into as a perfectly lubricated weather vane a.k.a. puppet, stuffed suit, figure head, empty shell, like Bush, like Reagan, like all the of the shills for the wealthy elite. Leadership isn't a necessary quality for the Right.