"So you can imagine how astonished I was last month when an American politician said that it was impossible to earn a billion dollars… What she meant was that it's impossible to get that rich without doing something bad — without cheating in some way."

Not exactly the way I interpreted it (emphasis on earn). Right or wrong, I think the vast majority of us think that "deserved money" is money earned from "work".

A simple example would be the billionaire Walton children: their fortunes inherited. Most people would argue that they did not really earn those billions of dollars.

On an admittedly slippery slope, for many, investing and other means where the money makes money is also not regarded as work (and therefore is not earned money).

To wave around the idea of "the American Dream", I suspect that many American's disapprove of any means of obtaining wealth that the average Joe or Jane are not privy to. This idea that you have to be born into money or have money to make money—we are (perhaps naturally) repugnant to.