But once again, the fact is that they don't. Not in terms of corporate support. Not in terms of government support. Not really in terms of listener support. As the poll posted earlier in this thread shows, the political interests of its listeners are very broad. If it WAS obviously biased, I doubt as many conservatives or moderates would listen. Why would they?
Asked and answered already. When public radio is the least objectionable program on the air, people tune it in or pop in a CD. As terribly biased as public radio's news reporting is, the other alternatives on the air are often much, much worse. Paul Klein's comments on television are even more appropriate to radio. People consume it as a commodity. Since most of what is on the radio is boring crap, people simply decide to listen to "some radio", and tune in the least objectionable programming that's on the air at the time. For many people, public radio is the least objectionable content on the air. It sucks, but the other alternative suck even worse.
But then, that's how the people running radio want it to be. Safe, bland, boring, with nothing that might make anyone change the station or turn the thing off.
Now, there are a small portion of public radio listeners who cough up money during pledge period. These are the folks who genuinely enjoy the bias of public radio's newscasts, because it reinforces their pre-existing opinions. And, there are some who might eventually find themselves subtly persuaded through repeated doses of low-level, semi-subliminal bias.
As for what effect my listening to public radio has on my opinions, I don't really "listen" to NPR. I have it on in my car when I'm on the road when "All Things Considered" is on the air. I keep the volume low, so it's really more like ambient background noise. Since they intersperse the news stories with trivial filler and cultural stuff, I might turn the volume up if something sounds vaguely interesting. Of course, when Fresh Air with Terry Gross comes on, then I turn the radio up and pay attention. I seldom listen to the radio on Saturday mornings lately, but years ago, I always looked forward to Car Talk. And on Saturday evenings, I'll listen to The Prairie Home Companion if I'm out in the car.