Hmm. Just looked this question up and apparently George Lucas agrees with you. I guess the Force would make it more fantasy.
What makes Star Wars fantasy and Dune sci fi?
Discussion
Imho, if there is a plausible scientific component, however far fetched, and no magic, mysticism, voodoo, pseudoscience, ghosts, etc. it is scifi.
Most people just lump them together. Scifi/Fantasy section.