I beg to differ. As fright laden a film fest as it would be...Terminator (ask Harlan Ellison) Alien and Avatar were Science Fiction. They had the scary bits thrown in to make them marketable. Nothing more. In fact, at the time of Alien and Terminator...it was probably the only way that Ridley Scott and James Cameron could get them to the big screen.
Alien was always supposed to be a horror film. That’s how co-writer Dan O’Bannon envisioned it - a scary version of ‘Dark Star’ which he had co-written with John Carpenter several years earlier.
That’s not the “fear-based” they’re talking about. They’re talking about Hollywood studios being afraid to take a chance on “risky” properties.
That being said, Alien is a horror movie that happens to be in space, but it is most definitely a horror movie. It’s go almost the exact same beats as Black Christmas and as such Halloween, it’s a slasher flick.