Population of Washington County and Iron County (St. George and Cedar City) 203,000 people and around 5,500 square miles.
Population of Madison County, Jefferson County, Bonneville County, Bingham County (Rexburg, Rigby, Idaho Falls, Blackfoot) 220,000 people and around 5,600 square miles. This doesn't even count the students who actually attend BYU-Idaho.
So really you have no point with that argument. Maybe next time.
Now I'm not saying that there aren't plenty of other valid points such as no spring in Rexburg, etc.