Just because an underdog wins does not mean that they were wrong (and wrong does not mean that they got the outcome wrong it means the probability). I am sure the people that make their living handicapping games dont know to look at past trends. It is sure a good thing you are here to point that out to them.
Vegas had BYU as the underdog to 3 teams TX (I guess they were wrong about that too), WIS, ND. That is 9 games Vegas had us as the favorite. That may have changed after the VA game but at the start of the season we were expected to win 9 (not 8 as I said). the 7.5 does not mean expected wins, that is the odds you are given so that Vegas does not lose money if BYU wins 8 or 9 games.