Answer: decadent and unscrupulous.
In the past, Japan was a very secluded place, and the information they received from other parts of the world was not always objective and complex. In the case of Americans, the Japanese believed them to be decadent and scrupulous. This is likely a consequence of the cultural differences of both places. While Japan is more conservative and traditional, America has always embraced liberalism and consumption, both of which could be seen as decadent and unscrupulous.