Do you feel it is racist to dress up as Native American? Why or why not?

I follow this girl on Tumblr.

http://mycultureisnotatrend.tumblr.com/

And she talks about how anything that copies Native American culture by modern society, especially those who aren’t Native American, is wrong. I respect her opinions a lot but for me I feel they are extra extreme because personally being a half Filipino/American person myself, I don’t really mind if someone were to dress up as say, a Filipino warrior like Lapu-lapu or an American Cowboy.

Well anyhow, what are your thoughts? A lot of her examples and defense always pertains to something along the lines of, “Whites could never understand the true meaning of being on the end of racism.”