First let me say that this does not apply to all Ute fans. Not even a majority of Ute fans. Most are decent people and a few (like my current bishop) are amazing people.
But it is becoming increasingly obvious to the entire internet that there is a significant portion of the fanbase that is proud of acting like disgusting children. Having lived in SL county my entire adult life, and had the misfortune of associating with a large number of them, I have come up with a theory about what drives this behavior that I am increasingly convinced is the truth.
Most people associate the state of Utah with the LDS Church and assume that everyone is a member so a significant portion of the Ute fanbase intentionally acts as rude, crass and disrespectful as they possibly can because it is embarrassing to the dominant religion and culture of the state, which they loathe. It gives them perverse pleasure to be mistaken by outsiders as representatives of that religion and culture.