What I doubt will ever be explained to us fans is why the referees didn't discuss the call BEFORE they announced and enforced the penalty and marked the ball ready for play? It's not that they discussed the call and ultimately reversed it — which I think was the right decision — it was that they did it after a dangerous delay caused by UT fans that if not for said delay, the review would never have happened.
The message that reversal sends to fans is if you don't like a call, throw trash on the field, and maybe during the time the game is delayed to clean it all up, the refs will reverse what was used to be an unreviewable call.