How many times have you EVER gone up to a Ute fan dressed in Utah gear anywhere - but especially at a non-athletic event, like a grocery store for example - and said to him or her (or to a kid): "Go Cougs!"
On other hand, how many times have you or your wife and kids been dressed in BYU gear and had someone flash the "I'm a double loser" sign at you and say, "Go Yewts."
Also, a little brother fan base will have bishops of wards who tweet out anti-BYU stuff and talk trash publicly about his Church school that alienates himself from 75%-plus of his ward. When I was a bishop, I never tweeted one thing negative about Utah because I knew, number one, that wasn't appropriate for the office, and number two, it could've alienated me from 75%+ of the people I was trying to get to come back to Church.