I believe "Reinventing Comics: Art" is meant to refer to both the pictures <i>and</i> the stories. Writing, after all, is no more or less an art or science than drawing is. I think the intent of the word "Art" is a catch-all for the creative aspects of comics.
Yes, "Art" in, in this case, being used to catch all creative disciplines, so if you've got something you'd like to discuss regarding writing of comics, feel free to post it there!