cheering for a team like Tennessee: Tennessee fans are, generally speaking, not arrogant and quite enjoyable to be with and easy to like. However, many Utah fans are as arrogant as the day is long and base their arrogance and their hatred of all things BYU on the fact that they hate BYU's sponsoring institution, and they'll tell you that to your face.
I don't not cheer for Utah because I have anything personal with the school, I don't cheer for Utah because I refuse to feed the fire of arrogance that many of their fans have.
It's that simple.