I new what it was going in (watched it a couple years after release), so when I did, I tried doing it from the mindset of (imagine this rewritten”. IMO, if you rewrote it to simply remove that one plot point...change it to ‘we must come here to survive’ instead of “we come here to rape you like indians”, the whole movie works fine.
But the agenda was their intent and damn the torpedoes. Cameron wanted to expunge his white guilt.
I lost all respect for him with that movie.
And the concept itself was hackneyed beyond belief. It’s been done many times. Prominently in Ursula K. Le Guin’s ‘The Word for World Is Forest’.