What is racist about avatar?

What's all the hoopla about the movie Avatar being racist? What is racist about it?

"Avatar" is being criticized by some people who allege it contains racist themes — the white hero once again saving the primitive natives.

Since the film opened to widespread critical acclaim over three weeks ago, hundreds of blog posts, newspaper articles, tweets and YouTube videos have said things such as the film is "a fantasy about race told from the point of view of white people" and that it reinforces "the white Messiah fable."

The film's writer and director, James Cameron, says the real theme is about respecting others' differences.

Also the Vatican has spoken out against the film for 'attempting to lead the flock away from God with his “Nature Worship”'. It criticized Avatar for flirting with modern doctrines that promote the worship of nature as a substitute for religion.

I see!
What's your take on this? Is Avatar racist? And did it 'attempt' to lead the flock away from God? Like anything can do that...abegi. It's a work of fiction...Get over it!