I think media has society believing certain stereotypes regarding Native Americans, which would have a negative impact on their culture. For example, look at the movie genre Country Western. They almost always "poke fun" at rituals and ceremonies. They also depict NA's as savages.
Media has caused harm to the traditional and native culture in the sense that it has made the young people adopt to the current way of life. It influential making people forget their past life or the life their fore parents prepared for them.