Oh, Joely, look at what you've done!
You start writing songs, and loving the music, and WE all start the tower of babble again and again and again and... I haven't been playing "this music" as long as mountain time, but I've had the same feelings. For years I always considered bluegrass as just another sub-genre of folk music. After all I first heard it on a "folk music radio show" back in the days when FM radio actually meant Folk Music radio. And I first read reviews and articles about it in SingOut!(thefolksongmagazine) and then I met some real bluegrassers and started plying along with them, and they were not only NOT folk musicians(!?!), but they were having the same arguments about the bluegrass genre.
IMHO - it has more to do with feeling than anything else. (not everything to do with it, but more to do with it)
I think you've just been initiated into the "folk world", if that term can be operable.