OU is a fanbase that can never be happy or satisfied. Sure they want to win, but anything less than a Big 12 championship is failing for them. I have family that got rid of season tickets (about 5 years ago)for the first time in 30 years because they were so upset with Stoops. They also don't plan on going to another game until Stoops is gone.
The "sick of Big 12" crap is their excuse for getting their ass handed to them the past 4 or 5 years by the likes of Baylor, TCU, KSU, and OSU. All programs that have been looked down on by OU fans for decades.