The most odious part of Cameron's carry on is the way he travels to remote villages in South America and parades them around like sideshow curiosities in tribal outfits. He implores us to leave them be, leave the noble savage alone (this is also the underlying message from Avatar, as I understand it) He never asks them if they'd like a refrigerator for food and medicine, an air conditioner or some roads built to increase their access to civilisation. Instead, they are just assumed to be more pure, a better way of living than the rest of us, and morally superior as a result. But nobody ever asks the villagers what they think. They're just told to stand there in war paint and look at one with the forest.
I haven't seen Avatar because once I saw the plotline I couldn't bear to sit through it. It's bad enough trying to watch a decent U2 concert these days without all the preaching being folded in.
Then there was the highly publicised event where Cameron was going to call 'high noon' on some bunch of climate change skeptics at a public debate. I think it was at an environment conference or film festival or something. But as the date approached he asked to have the rules changed many times before pulling out altogether. I'm sure the reason is not to give the skeptical point of view any airtime, but it just makes him look foolish and clumsy.