Most scientists don't take political positions. They make observations, and when a consensus is reached, they sometimes take actions. For instance, when it became pretty clear that lead was dangerous, there was a movement to remove it from gasoline. This became political because some interests were only interested in quarterly profits, not long term costs to taxpayers. Fortunately the taxpayers won. For instance, there is really good science linking the buildup in the environment of lead to the increase in crime, and the decrease in crime of the past decade or so to the decrease in lead. It is not just correlation, cut actual causation.
Now, as far as NPR is concerned, compared to Fox News of course it looks biased. NPR is not going to invite John McCain on the air to talk about when he was a kid you could kill black people, and know he has to deal with a black man, as he has been saying this past week. But the thing about NPR is it probably does a better job of using the public air waves than other.
Here is the rub. Fox News can say and do whatever it wants because it does not use free public resources. This is the key. Free public resources, not funding by the government. The government funds lots of things, and that does not necessarily absolutely limit speech. For instance, many churches take money for schools, which frees up money that they then use to do stuff like encourage people to attack people going about their day to day business. For instance, one church in my area bought cameras so they could photograph people going into a gay club. But radio stations were given public bandwidth and were supposed to use it responsible ways. I think NPR is responsible and balanced compared to some of what I hear on the AM stations. AM stations are using free resources. We could take it back and make a great deal of money leasing it to other agents. We don't. They agree to use it, and should be more responsible.