They are wrong.
BYU has played Utah 9 times as a top-15 team. The average score of those games is 37-14. Including a drubbing of 48 points in 1983.
The only single digit game was in 2001 when Utah was 7-2 and playing really good.
When BYU is ranked high, we show up against Utah.
BYU 37
Utah 17