Here's a brief argument that I jotted down while listening to the discussion yesterday:
1. Only actions, in contrast to mere objects, can be moral/immoral. (Jacob)
2. Art objects, in contrast to mere (perhaps aesthetically pleasing) objects, are always at least artifactual.
3. The artifactuality of art objects makes them, at least in part, performances. (Dutton)
4. Performances are actions.
5.Therefore, art objects can be moral/immoral.