In a funny way, I would not include most protest songs in the "conscripted" category anyway. I guess it's OK if they were written as an outlet of the writer's emotions and thoughts - but not to serve a particular organisation. After all, every song presumably has something to tell, some message to pass. To be "conscripted" its creation must have served some other purpose than simply the writer's need to express themselves.

And sure, there is a fine line between simply "expressing oneself" and propaganda, and the distinction isn't clear sometimes.