An observation (that I'm sure I'm not the first to make): iTunes Radio is an Internet-audio streaming service that has nothing to do with radio. When it was introduced, The iTunes desktop feature that lets one listen to the Internet-audio streams of actual radio stations was renamed "Internet." Yes, the thing you can only hear using the Internet is called "Radio," while the thing you can actually listen to on a radio is called "Internet." The NPR station is the first thing in iTunes "Radio" that is actually related to real radio.
More observations: The re/Code post about the NPR station notes that someday soon, you'll be able to listen to individual NPR affiliates via iTunes radio. One can already do this by using the OSX iTunes' "Internet" feature to search for individual stations of all kinds, including the BBC. (Note: This works with Airplay, unlike the new NPR station in iTunes Radio.) Downside: the interface is just awful, very sub-par for Apple; the promised NPR-affiliate iTunes "Radio" stations will basically be an improvement in ease-of-use marketed as a new feature. Oh, and I guess it would suddenly work with iOS, too.
Or, you could just use TuneIn, which is free, can be accessed via the Web in OSX or through its iOS app, and has long offered access to individual NPR stations, every BBC radio station, and just about anything else you'd like to listen to from any radio station in the world with an Internet stream. I've long wondered why Apple didn't just buy TuneIn and build it into iTunes. I guess they'd rather re-build it from the ground up. I just can't figure out why it took them so long.