I think it's because Williston State is a very small junior college and is flying under the radar than anything else. Williston also does not use a logo, and their uniforms either say "Williston State" or "Tetons". I'm sure the Sioux tribes would like WSC to also change it's nickname, but it hasn't been brought out into the spotlight like UND's has. Also, most people probably don't even know that The Tetons were a band of the Sioux tribe (the western most band, hence the name...).