His myth looms large: Barry McGee, tag name “Twist,” San Francisco–based art-school graduate, graffiti artist, and vital player in the emergence of the Mission School aesthetic. Following its breathless tributes to Shepard Fairey in 2009 and Os Gemeos in 2012, the ICA Boston is hosting McGee’s traveling survey, which originated at the University of California, Berkeley Art Museum and Pacific Film Archive, where it was organized by Lawrence Rinder and Dena Beard. While the show offers a tempting occasion to rehearse the problematics of populist curatorial programming, those critical arguments