The audience experiences catharsis when they watch the movie Avatar because they feel that the problems of Pandora correlate with the problems experienced here on Earth.
Though painted with broad strokes, James Cameron’s ‘Avatar’ clearly demonstrates to the viewer a definite resemblance between the Na’vi’s experience on the planet Pandora and our own unfortunate and continuing plunder of natural, non-renewable resources on Earth. With a certain measure of hindsight and disconnect, the audience can vilify the actions of the RDA Corporation as they destroy a perfect, untouched ecosystem while also experiencing a level of catharsis when the Na’vi react in defense.
(Source:imgflip.com & imdb.com)