Wild Bill Hickok is haunted by his dreams of a giant white buffalo. So much that he travels the West to find the beast. Along the way, Hickok meets Crazy Horse, who is also searching the plains for the giant white buffalo, who has killed Crazy Horse's daughter. Hickok and Crazy Horse team up to kill the elusive buffalo.
The movie "The White Buffalo" expresses in a way the same fear held by whites when the Ghost Dance was given. Take the tradition that the White Buffalo Calf will bring in an era of peace in which the First Nations will prosper (something colonists simply can't let happen of course) and retell the story from the conquerors' perspective that the White Buffalo will go about killing innocent white settlers and disrupting the economy.
In short, it seems the movie's White Buffalo is a stand-in for the marauding savage Indian. Look out, America...buffaloes and Indians on the warpath!
In a Native version of this story, the heroes wouldn't necessarily kill the monster. They might reason with it, gamble with it, trick it, outmaneuver it, leave it trapped, or free it from whatever spell it was under. That monsters are for killing is a typical Western trope.
For more on the subject, see Hercules vs. Coyote: Native and Euro-American Beliefs and America's Cultural Mindset