I wonder, listening to any style of music is about enriching your life in some way (even simple enjoyment), good for general happiness. Is Trad Folk socially regressive though? I reckon not more than any other style (think about the range of lyrics in rap music, from good to bad).
Because trad songs are often so seemingly distant from modern life, it makes you do a bit more thinking about the original context, espeically if you want to sing it truthfully. It often tells us things we don't want to know, can't easily grasp, about subjects that are 'difficult'. For me it's one cure for all the mass generalisations about the past.
And, surely, having to think about things from another point of view is the essence of 'socially progressive'? That there's many sides to every story.