It is interesting how I answer your point and yet you quote something else. I specifically mentioned Plato’s Stepchildren which has no more explanation of the mysterious powers within the episode than Star Wars has. The episode mentioned the mysterious and undefined chemical compound kironide. It never explains how that chemical results in the psychokinetic powers the Platonians exhibit. Ben’s description of the Force as an energy filed created by all living things that surrounds and binds is a more detailed description than Plato’s Stepchildren ever gives. Such psychokinentic powers can not be proven to exist in our world, yet the Platonians have them and the Q have them to an even greater extent. Gary Mitchell was developing them, as was Dr. Dehner. None of these are ever given any detailed description. Isaac Asimov had his character of The Mule who could reprogram people’s minds. He didn’t have to touch them and could do a whole room full of people at once with the aid of a special musical instrument. He could even kill with his mind. He later (post ROTJ) expanded that to an entire planet with The Mule being an escapee. He had a robot initially learn the skill and teach another robot who in turn established the planet. Asimov is one of the three greats of science fiction and he didn’t hesitate to have characters with mental powers that defy science and logic.
So the argument that the Force makes Star Wars a fantasy does not hold up to comparison to established science fiction content.
I see SW as having fantasy elements due to several things. The force being just one of them. The robes, the mystical elements that give nods to supernatural reasoning for things happening the way they do. The classic knight in shining armour trope with the (not so) damsel in distress etc.
The old wise man who is obviously a nod to the wizard type of character you would see in a typical Tolkienesque fantasy. The swords being used as a “elegant weapon of a more civilized age” definitely suggests a King Arthur and knights of the round table. The classic good and evil sides doing battle…that they take place in space is incidental in a lot of cases.