Barnstorming on an Invisible Segway

Sure, and I don't find that an unreasonable terminology. I'm just noting "fiction of the fantastic" as one possible meaning of "fantasy," and one that's well defined as a taxon. A category that includes genre fantasy, and science fiction up to a particular reader's/viewer's cutoff point of "not rigorous enough"—like E. E. Smith saying that the Lensman series was science fiction but the Skylark series was not—strikes me as taxonomically bad in the same way that "invertebrate" is taxonomically bad: There is no actual trait that all invertebrates have in common that all animals don't have in common.