The free culture movement and the pirate movement are two quite different things. The latter is fair game for ostracism by those who value Rule of Law. Free Culture, however, is not about expropriating things into the public domain but creating things that are born public domain, basically a (largely failed) effort to bring the (IMHO admirable) open source ethic to things other than software.
David Newhoff, in This is no time to be devaluing creators, seems to be trying to conflate the free culture movement with the tragically unfortunate trend of employers who want to pay people in “exposure” or “experience.” That phenomenon harms most if not all workers, creative class or not. The former would benefit more from better labor law protections than from better IP protections.
Another reason a middle level (or middle class) niche in cultural product is difficult to carve out is the “long tail” nature of audience share distribution. So it will probably always be the case that the nightclub acts vastly outnumber the rock stars, but also that the amateurs will always vastly outnumber the nightclub acts. Making assertion of IP rights the main strategy against the unpaid internship phenomenon looks from my outsider perspective like an attempt to guildify the creative professions by erecting entry barriers. I actually have nothing against this approach, as I’m pro-union. But should the high wall be between established professionals and semiprofessionals? Or between semiprofessionals and amateurs? Perhaps the creatives should go full trade unionist and adopt a formal apprentice/journeyperson/master hierarchy. I think paid apprenticeships are the only truly appropriate answer to unpaid internships.