"but they are still art to me, at least some of them, Planescape torment being an example."
You seem to be implying that in order for something to be art it has to be good or of really high quality. That is illogical.
A painting, for example, is art whether it's a prize winning one or some doodle by a kindergarten kid.
So, *if* one considers games arts not only should 'high quality' games be art (FO, PST, BG, or whatever) so should the bad ones (POR2, TOEE, DTU, etc.).