BYU got invited to the Big 12, so the Big 12 was suddenly worthless and Utah fans wanted everyone to know it.
After a couple of years of bashing the Big 12, because it invited BYU, Utah sunk the PAC 12 and scurried to the Big 12.
Utah fans couldn't roll back the clock and undo the online Big 12 bashing from the previous 2 years. Instead, they continued to act like they were somehow superior even while accepting the rescue raft.

Yeah, everyone wants them to lose.