idk about betray humanity. second movie made it pretty clear that the humans weren't there for the good of humanity - it was to profit off (and destroy in the process) Pandora's natural resources for the benefit of a few rich billionaires
Would’ve been interesting if the whale blubber they were harvesting in the second movie cured cancer instead of being some luxury, “it makes you look young” juice.
Anything organic like would be more efficient to synthesize after it's discovery. If the writers said it can't be synthesized, it would just be the writers pushing a false dichotomy. Very few things can't be synthesized and the things that can't, are harvested responsibly, like horseshoe crab blood.