As a non-American, the way I listen to American public radio is via podcasts. And the programmes that I listen to are, in general, about topics I find interesting.

The factory radio in my vehicle (which is almost as old as me) does not have the capacity to play a podcast and I do not own an mp3 player. Also, the public radio station plays programming which is produced by National Public Radio during my commute (I'm not listening to Wayne's World Radio or the like). This programming is, in my experience, fairly neutral news, which varies from super serious, important news to fascinating fluff pieces.
I find that when left to my own devices for news, I have something akin to confirmation bias, where I only pick news that is really important and interesting to me, which tends to be a fairly narrow picture of the world (mostly science and tech news). NPR's news tends to push my boundaries enough that I get a better picture of what is happening in the world. So if I were to download podcasts of NPR news programming, I would the be getting the same service also without paying. I guess I could contribute directly to NPR instead of local station (which in turn pays NPR for the programming) but if everyone did that, there would be not local stations, which would possibly mean less funding for NPR, which would negatively impact their programming, which I find valuable. It is really the same scenario on a bigger scale.