This merely confirms what I already know - that the American public tends to be very conservative. Consequently, any form of left-leaning opinion, be it a tv or radio show, or a political program is unlikely to attract any significant following. Their popularity, if any, will be at best limited to very narrow audiences linked mainly to universities.
The key reasons behind fundamental conservatism of the American population are: multiculturalism, which produces inter-group rivalries and prevent the formulation of broadly defined political interests and agendas, and the absence of established institutions guarding, promoting and legitimating left-leaning opinions. The only places in this country where leftish opinions can find some institutional support and sanction are universities, which are for the leftists what zoological gardens are for animals - collections of exotic species.
Most European countries have mainstream institutions (such as political parties or newspapers representing a political orientation) that express, represent, promote and legitimate a variety of political opinions from left to right. The US, by contrast, lacks such institutions - the one that exist represent the views of the ruling oligarchy ("many voices, one chorus, as Michael Parenti aptly described it). All social or political institutions espousing views that threaten the interests of the ruling elite, corporate or state functionaries (such as unions, or "third" parties) have been systematically decimated, coopted, or marginalized in this country.
The democracy in this country is but a Potemkin village covering up the fundamentally autocractic nature of the US state and the oligarchy that controls it - you can espouse any opinion or preference, no matter how silly or weird, as long as it does not threaten the interests of the ruling "nomenklatura." This is not that much different than the Soviet-style state, where you could form any interest group, from canary breeders, to community gardens, to nudist clubs, to yoga classes, to fan clubs, to butt-fuckers leagues, stamp collectors associations, celebrity cults and so on and so forth - EXCEPT an independent labor union or an independent political party.
In the absence of institutional representation in the public sphere, it is not a surprise that left-leaning opinions are not popular among the US public, fragmented into a myriad of cultural identity groups.
wojtek