Many of us Lakota immediately knew the difference because those photos of the dead at Wounded Knee are burned into our minds. It is an event that we commemorate annually.
The shot of the dead at Wounded Knee occurs at the 3:30 mark.
It's funny to hear Oprah say she attended a powwow. More to the point, she staged a powwow for the benefit of her cameras. See Oprah Visits Navajo Nation and Demands to See a Powwow for more on the story.