The Last Airbender casting

I found this on Alas, a blog, which is from the angry black woman, and I thought I would share it here since it's interesting how M. Night Shyamalan seems bent on ruining the image of Avatar: The Last Airbender live-action movie by casting all white people. It's disappointing really, because I love the series. I feel like something very important will be lost in this translation of Avatar. I know this is an American-based cartoon, but it's set in an all Asian world, and not just the "standard" stereotypical depictions. I guess nojojojo says it best here:

The thing is, all of these stereotypes are present in Avatar to some degree. But because the whole world is Asian, they’re lost in a sea of non-stereotypical, non-exoticized, perfectly normal human beings. How amazing is that? Not only that, but Avatar actually depicts different Asian ethnicities. Though this is a fantasy world, there are clear allusions to the Inuit, Koreans, Mongols, Tibetans, several flavors of southeast Asian, various Indians, and more. The Chinese- and Japanese-analogues of the story actually come in several varieties (Earth Kingdom and Fire Kingdom, Kyoshi warriors, etc.).

It surprises me most because I don't understand the justification for this. Couldn't M. Night have easily cast some up and coming Asian actors? Certainly these white kids are not so fabulous that they can outshine some equally talented Asian actors that would at least be keeping the flavor of the cartoon alive...

At any rate, I'm hoping that there will be some quick changes to the cast before filming begins. It would be different if the variety of Asian cultures didn't play so significantly into the story and world of Avatar, but it does, and changing the ethnicity of the characters is too significant to ignore. I mean, isn't it a little strange putting these suddenly white characters into an identity rich with Asian cultures??

I'll probably still end up seeing the movie, but it will suffer with this cast...
Thoughts?