Ha, I did happen to leave that movie wondering when I would read an article like this. I will compile/reiterate and expound on a few points.

1. Yes, it's Dances With Aliens. This movie was a tech demo set to a classic archetypal story of historic human nature. The Native Americans were not the first, nor the last indigenous people to have been push aside and beaten by a more and technologically superior powerful imperialistic society. Many a debate can be had over the "might makes right" dogma, and the duplicity of "civilized" society killing for resources.

2. Yes, they did specify that the soldiers in the movie were mercenaries. Mercenaries have been a punching bag for movies for a long, long time. I believe that anyone who values national military service would also sneer at mercenaries, because mercenaries do not fight for nationalism nor ideology, but for the shear fact that they are good at killing and can make a job out of it.

3. Yes, the movie was written or at least conceptualized way before our current international military efforts came about.

4. Any allegory to present circumstances you interpret are egocentrism. You can't help it, that's just the way our minds process information.

5. Oddly enough I believe you would have appreciated the moral ambiguity that was left out of the movie for pop appeal. The humans were on Pandora mining "unobtainium", but why? Because the human species needed to it survive. Forget for a moment any sociopolitical message that would be interpreted by our depletion of our own planetary resources, and think about the motivations of the "evil" characters that were literally fighting for our races survival.

6. Did you just now realize that Cameron is liberal?