More on the question of photographing public art

Peter Friedman has some thoughts on the public art copyright infringement lawsuit I mentioned a couple weeks ago here. He endorses the sentiment that "any scheme that involves paying to photograph seems antithetical to the public interest," and he also thinks the photograph at issue is a fair use "because [it] stands on its own as a creative work. [The photographer] has taken a work embedded in a sidewalk in front of a public building and made it into a beautiful image that evokes both dance and confusion in a world full of complicated instructions seemingly sending us in a myriad of different directions."

Justin Silverman of the Citizen Media Law Project (whose sentiment that paying to photograph is antithetical to the public interest Friedman endorses) has a more thorough analysis of the fair use issue, running through each of the four fair use factors that courts apply, and concluding that, "all in all, ... it's a hard call."

Turning back to the "public interest" question, though, I want to ask: what role does the fact that the work is public play in the analysis? Is it only antithetical to the public interest for artists who make public art to retain copyright to their work? What is it about public art that warrants keeping it "completely open to the public" (i.e., as lacking the same copyright protections that apply to other artworks)? Don't all the same issues regarding incentives to create apply in the case of public art? I just don't see the argument for treating Jack Mackie's sculpture here any differently than the way we treat any other work.