The question to ask them is who has been doing all the extra useful work that created the growth?
After all we already KNOW that the poor - and actually a good majority of people - haven't been getting paid more for a couple of decades (after inflation). And that the rich have gotten a LOT more (salaries and profits). So it is no surprise that the extra spending comes from the rich. But that they got the money (by weakening unions, lowering wages, etc) doesn't mean they EARNED the money.
Paul