Katrina - or more specifically, the propaganda masqurading as Katrina coverage - has apparently provided sufficient cover for those who previously lacked the stones to come out of the closet and suck up to the press, allowing these peacock displays of how much more compassionate they are than those "other" Republicans. In this, Mitt Romney isn't so much a surprise as a disappointment.
He's a packaged commodity, marketed to look appealing without really much there when you take a closer look. Sort of like one of those candy apples that you buy at the fair. Once you get past the candy, the rest of it is usually mighty sour.