Fair enough. I don't think complete agreement in judging art should be the standard, though. Aesthetic values needn't be exactly like cold hard facts in science. Art relates differently to different people, given our social and psychological backgrounds.

What's more important than agreeing on the particulars of artworks, however, is the development of an aesthetic perspective so that you can appreciate, at least, that there's such a thing as high art, and so that you can see the aesthetic qualities of absolutely everything. The aesthetic values would be objective not in that the particulars are identical for everyone, but in that the aesthetic perspective is available precisely to those who are engaging in scientific objectification (because both involve detachment from the personality).