I've been analyzing the stuff called "bluegrass" for a while to watch Satan's influence. You posters are correct in observing there are performers pretending to be Christian.
But, there is a new and even more disturbing development. The music has a strong tradition of being performed by males--nary a female performing it anywhere.
Now, besides Rhonda Vincent their are young women stealing the music from the men who developed it. And, these younger women do not bother with the pretense of Christian themes. The worst one I'm studying these days is named Sierra Hull:
https://www.youtube.com/watch?v=_aQonnNSATk