I truly believe there was a strategic move on their part to make BYU irrelevant. It wasn't malicious or spiteful... it was simply a strategic move to build an empire. I hated it and despised it, but I think it was a smart "Business move" on their part.
I actually have little doubt BYU will petition to add Utah to the BIG12, but I think it's a mistake. BYU's best path to success is to eliminate local competition, gobble up as much top local talent as possible, and clearly become the region's top program.