Nobody wants to say a disparaging word about an experimental reverie on Allen Ginsberg from the filmmaker who hit The Times of Harvey Milk out of the park. But Rob Epstein’s not-quite-docudrama, co-directed by Jeffrey Friedman, thrills us with Ginsberg’s brilliance only to manifest the difficulty of making a movie about it. With a glamorized, gay-iconified Ginsberg in the form of James Franco, who registers the poet’s mind and spirit strongly, this structurally iffy contrivance trudges through the precedent-setting obscenity trial from which his publisher emerged victorious with a long-standing best seller, along with several silly animated rhapsodies dramatizing the poem itself. Ginsberg once described his most famous work as “a promotion of frankness” that he considered “socially useful” for its era. This film seems similarly duty minded, but at least it has the sense to give in to enchantment once in a while as well.