Well the user said it's not intended as a scray movie.
Going by that interview answer Cameron doesn't outright say
Aliens is an action movie per se (I think).
But he says:
Quotebut more intense, and I like to use the word, exhilarating. Because I think you get exhilarated by the intensity of the kind of action that's in this film.
I leave it to the native speakers and film experts to conclusively categorize this type of movie.
(I gotta say, I'm a bit impressed. I didn't know Cameron was this level of slick with words -- and spontaneously in an interview that is)