John (of John and Belle) discusses the whole Alien quadrilogy (tetralogy?) here. Well worth a read if you like the films.
Cameron has more than once acknowledged that he conceived the Marine mission to LV 426 as a study of the Vietnam war - in which, on his analysis, a high-tech army confident of victory over a supposedly more primitive civilization found itself mired in a humiliating series of defeats that added up to an unwinnable war.
This just shows that Cameron doesn't understand his own work. The key scene in Aliens is when the gorgeously butch Vasquez joins hands with the effete WASP captain, putting aside all superficial enmity in homo-sapiens-solidarity suicide bomb against the anti-human.
If all the man wanted to do was make some sort of philosophical point, but there was no way to make that point allegorically, in a movie - except by making the movie no fun - then was it really wise to make a movie rather than write an essay?
There's bags more to read if you follow the link. I think I'll ask for these books on the philosophy of the Alien films for my birthday, together with the boxed set of DVDs.