I have lived in Utah for my entire 6 decades, What I have found when it came to Utah fans that the majority of the adult fans are good people, they don’t hate BYU. Yes, there are a few knuckleheads who make the rivalry into something bad.
The students as a whole are the ones that take it to the nasty level. It was students that harassed Hall’s family. I am not saying there are not bad fans, I just have not run into them as much.
I once sat in a sea of red(adult fans) with my Blue cougar gear on and you know what? we had a good time ribbing each other.
I know for a fact that KW does not hate BYU, he is competitive, and wants to win, but he has never said a negative thing about BYU itself, he has commented on how some BYU fans treated his wife in a very unkind way. I have talked to personally and my neighbor works for him.
There is a faction of Utah fans that has a real issue with how the church “runs the state”, How the good members of our church treats non LDS people in their neighborhoods. Trust me, some members are some the biggest AHoles I know.
I am not saying other peoples experiences did not happen, I just never had an issues with any Utah fans personally.
The other cause of the nastiness is the local media who promotes the “Holy War”, which term I have never liked. They stoke the bad feelings and push for a nasty rivalry to promote their media ratings.
That is my perspective, I am sure there are other Utah BYU fans that may be different.
One thing that may make me different, is when I go to Utah to watch the BYU game, I do not expect or look for bad behavior from the fans… Not sure if that helped my perspective, but that is how I roll,