The sentry gun sequence is probably the most damaging inclusion into the alien series. Because even though humans have rushed human gun emplacements since the civil war in the attempt to "overrun" them, nobody ever thinks of it as a human tactic. It's just a tactic ants use to overrun other bugs on a sugar cube.
It becomes instinctual and mindless over tactical.
And thus the comics, and guys like the Strause brothers, and fans that think like them take things like the sentry gun scene and use it to characterize the Alien.
Even Cameron wanted them to be smart. Check the cutting of the power (with commentary). Watch the Aliens try to slide fingers in and pick the lock when the marines flee into the airducts.
Yet he damaged the perception of them by adding those guns because every writer, director, fanboy impressed with Aliens uses "their just bugs," to justify their stories.
Sad since the very definition of the title character is suppossed to suggest foreigness or unfamiliarity.
I don't blame Cameron for Aliens. I enjoy the theatrical version of the film immensely, and wouldn't mind the SE if it wasn't for the inclusion of the new scenes shatters the pacing. But I'll always be semi annoyed that he opened the door and started the, "Aliens are dumbazz bugs lolz," movement by including those sequences.
People don't even look at the facts concerning the story anymore. You go to imdb and the marines wasted hundreds maybe thousands of Aliens because they are mindless creatures that need to be squashed and are only dangerous when you don't have a weapon. Despite the fact that the marines didn't have that much ammo, and even AFTER the sentry gun scene and the ops battle there are still enough left to make Ripleys motion tracker go haywire.
I don't think Cameron knew the sentry gun scene would have its own mini legacy. Or he wouldn't have included it. I don't think Cameron wanted the Aliens to be ants. I think he wanted them to be the Viet Cong, or the Afgani forces that beat off the U.S. and Russia respectively.