I am sorry, I had to bring my kids to school and had to run and I just got back.
I think that the article speaks for itself. Contrary to popular opinion, the indigenous Green movement was largely born in the racist forests of Germany going back to the 1800’s. The Nazis incorporated this movement as their own and even trumpeted it as such. This ‘green’ streak of the Nazis ‘fooled’ a lot of people, including Leni Riefenstahl. After the war, much like German environmentalism, Leni and Lucky Lindy became international environmental activists as a way of getting out from under their compromised Nazi past. The point of the article is that this conversion is a very shallow one at best. Leni Riefenstahl has just gone from one bad marriage to the next. Today, the enviromental movement hates people in general. Environmental multiculturalism, in full display in Avatar, still has its roots in the German green volkisch movement of the 1800’s. Volkisch means people when translated literally into English, but it really stands for indigenous racism.
I think Cameron has a political obsession with this broad tradition. In addition, as a well-rounded film maker, he doubtlessly has deep knowledge of Riefenstahl's work.
Maybe I miss the point, but I think it's saying too much to specifically say that Cameron is obsessed with Riefenstahl. They have some things in common. That doesn't mean he's obsessed with her.
Volk (in this sense) really means People, in the same way the term for themselves used by almost every native tribe in the world means People or The People.
The implication of course, by both the tribes and the Germans, was that other people weren't really people at all.