The people saying it know that BYU means the main campus in Provo, don't let them bother you too much.

Ironically, they can only say BYU-Provo because there is so much demand to attend BYU that they opened two other campuses to meet demand, plus programs in SLC and Jerusalem. The fact that there is a single University of Utah instead of a U of U system with other campuses in Saint George or Ogden is a sign that there isn't any demand for a U of U education.