THe writer, Lighter, is absolutely clear about this. What puts her in mind of folk music is the sense that the music:

"Resists the rhythmic and melodic efficiencies...of chart pop in favor of something slower and more irregular, with few hooks or choruses."

This would also be an apt description of an unaccompanied folk ballad, so I think it's a pretty good analogy. It doesn't mean she's saying it is folk music. I hear plenty of music that puts me in mind of something it isn't. I think humans like to see connections between things.