Maybe the real reason Tron and films like that are so scary is that they posit a world where computers are pretty much running everything and doing computer things and only keep us around to fight for their amusement.
Deep down we all know interstellar combat won’t be exciting, at all. It’ll be asteroids hitting cities from millions of miles away, spaceships instantly flash-fried by lasers on the other side of the sun. There will be no human drama, only instant cessation of life. Any movie you see them fighting with swords in space, flying their combat starfighters in space, infantry advancing in ranks with a 3d banner of their Fearless Leader held over their head is impossible. The only way that could ever occur is if somebody built a perfectly functioning society — or a robot that built such a thing — and then let us fight on the surface, like two cavemen strangling each other on the hood of a car. Star Wars, Firefly, Battlestar Galactica and Avatar all describe the worst-case scenario for humanity. They are neither more nor less realistic than Tron.