Here's one possible answer: His Dad's political ambitions were crushed by the Dem media after a casual comment. A quote from Charen:
You might suppose that the anti-Vietnam press corps might have approved of this demonstration of independent thinking. But Romney was, after all, a Republican. Moreover, as White makes clear, he was a particular kind of Republican — naïve, innocently moralistic, and old-fashioned — qualities that the liberals in the press were inclined to loathe. Within days, the “brainwashing” quote was everywhere. Eugene McCarthy added a cruel but amusing quip that no brainwashing was needed as “a light rinse should have been sufficient.” Romney’s polls tanked. He was finished.