it is arrogant to assume that USU students and players want to go to BYU and will jump ship at the first opportunity. BYU hasn't recently proven that they ARE the team to move up to.
BYU can use all the fans they can get. You may not care, but overall, the program wants and needs more fans (even casual fans). My brothers and I used to be fans of both BYU and UU. After attending games and seeing how some UU fans acted and hearing 'smack' from others, I lost interest in them and my brothers completely turned away (actually root against them). Does UU need us as fans? No. Would it be beneficial to have three or more 'extra' fans (we all have families)? Yes.
I played multiple sports and didn't see a need to talk smack in any of them. Smack talk doesn't equal skill. Fan smack is even weaker.