But he is a moron. In the same sense that before that he was a baby. Its symbolic. He doesn't know anything about the place he is in, nothing about the ecosystem or the culture of the Na'vi. They aren't being mean to be funny, they just won't recognize him as an adult until he learns. IE grows up from a baby, stops being a moron. It is symbolic of his growth and journey. Its called tough love.
Yhea the humans villains where bullshit, but I still hated them. And you are supposed to hate the bad guys. I didn't see it as a humans are evil and nature is good type story to be honest. Just the filthy corporate out for nothing but money are evil.
I don't think of everyone who hates avatar as an internet poser, only the ones who post one sentence responses.