From TVTropes: Mighty Whitey

A common trope in 18th and 19th century adventure fiction, when vast swathes of the world were being explored and properly documented by Europeans for the first time, Mighty Whitey is usually a displaced white European, of noble descent, who ends up living with native tribespeople and not only learns their ways but also becomes their greatest warrior/leader/representative. Extra points if he woos The Chief's Daughter along the way; an unfortunately common variation that perpetuates into present-day media is that she will continue to love our hero even if he is directly responsible for the death of her husband, brother or even father.

http://tvtropes.org/pmwiki/pmwiki.php/Main/MightyWhitey

How is this not exactly what Rachel Dolezal did?

"I will go live among the black people and learn their ways and they will make me their leader."

It's fine to affiliate yourself with a different race or culture, but the way she went about it seems really gross and imperialistic.