Just my opinion, but flying the flag upside down is a sign of dire distress, which would seem to apply to the producers' views of American politics given Frank's ability to ascend in it in the way he does. As for omitting the stars, there is a difference between implying that the country is in distress with an inverted stylized U.S. read more
An upside-down flag is generally considered to be either a symbol of distress, or a sign of disrespect. read more
It can be insulting/demeaning if used improperly, but it's entirely appropriate to fly it upside down as a means of signaling distress. edit: the relevant portion of the Wikipedia page: Flying an American flag upside down is not necessarily meant as political protest. read more