To be fair though I think the arguement that sci fi is a genre of cinema is itself pretty questionable. I spose you could argue it could have been viewed as such in the 50's and early 60's when it implied a certain kind of film more often and perhaps thats why its reffered to. SInce then though I think you have clearly many different kinds of films, dramas, thrillers, horrors, comedies, etc that all use that setting.
So arguing over whether Starwars is a sci fi setting or not seems much less important to me, if you wanted to argue the films merits then perhaps the better arguement would be whether its well made cinema with intelligence and dramatic weight to it. I mean Blade Runner, people don't generally think thats a great film because it provides us with a direct warning to the evils of making slave robots in the future, they think its a great film because its well made, has strong drama to it and uses that setting to say something about humanity, mortality, religion and slavery.
You look at Empire and I think it is clearly a well made film and whilst it does spend a good deal of time looking to entertain its also I think quite an intelligent film. Its a story of Luke's simplistic and egotistical idea of what heroism is being undercut by Yoda and Vader(and even earlier in the film we see him more vulnerable) plus you could argue a bit subversive at the time in terms of Leia ultimately being the one saving Luke and trying to save Han rather than the reverse.
I think thats actually alot of the reason The Last Jedi was so hated, it tried to claim Starwars had been merely simple heroism previously and indeed that it has been sexist, neither of which were true. It has moral complexity to it previously and unlike the Last Jedi it had the guts to stick to its story.
