the game was VERY physical from BYU's side of things. They were VERY motivated about the ACC snub, and instead of running up the score, they played physically and took it out on the players. There were some absolutely vicious hits going on during the game, which happens during a FOOTBALL game, but you could tell that BYU had a chip on their shoulders about something, and they were taking it out on the UVA players. THAT is the UVA fans are crying about. It wasn't dirty play imo per se, but it was VERY physical play, and it was motivated by the snub, and they took their aggression out on the field.
Now for someone who doesn't care about the snub or even see it as an issue, or see BYU play every week, if you thought that's what they did every week, you'd probably think the same thing. And you'd be wrong too.
Instead of taking out their aggression on the scoreboard, they took it out on the players themselves. The UVA players paid the price for the ACC's stance towards BYU, and their fans noticed it (their players probably did too).