You're right. However, venue changes are rare. The judge's decision in Barry Morphew's case was exceptional. Among the many factors that made it difficult to get a jury pool was the small size of the county in which the trial was set (about 18,000). The case was moved to a neighboring county with a population about 50,000, where the judge thought he could draw a jury pool sufficiently large to find twelve impartial jurors notwithstanding the publicity surrounding the case, which had been promoted by the District Attorney in ways the judge found concerning.
Kootenai County is the third largest in Idaho, with about 180,000 people, which should support the more common approach to venue change: to reserve ruling on the motion until after an attempt has been made to seat an impartial jury in the origninal jurisdiction.
For a typical rationale, see:
Order on Defendant's Amended Motion for Change of Venue, People v Pankey