Responding only to the OP, not having read everything since... Folk music CAN be political. All genres of music can make a point (political or otherwise) if they wish to. But punk is the only one I can think of off the top of my head where the foundation of it seems to be "We want to protest... About..."

No, broadly speaking. Folk music isn't political, and folk musicians aren't political. First and foremost, surely, folk musicians are musicians? 99% of 'em anyway. Some recycle songs because they want to repeat the point; others recycle the songs simply because they love that melody, love the well-crafted lyrics. Etcetera. I can draw you 101 shades & nuances between those two poles, but I don't think I need to.

For some the music is all; for a very, very few the music is a vehicle to carry their message. On those grounds alone (if you accept the point as valid), there cannot be any "all", whether it's folk, rock, pop, acting, writing, emptying the dustbins… ;-)