It was overturned because his momentum/body lean was taking him to the ground and the ball didn’t survive the ground. Dez didn’t complete the process and under the rule that’s a no catch. An act common to the game or a so called football move doesn’t matter when a receiver is ruled going to the ground. The rule really isn’t that hard to grasp but it’s like trying to explain Chinese algebra to some here.
Wrong, just plain wrong as pertains to the 2014 rule which was the governing rule for the Dez play. The excerpt I posted precedes the "going to the ground in the act of catching a pass" clause. The "act common to the game" is preemptive to "act of catching a pass". If the former is ruled to have occurred, the later does apply because the act of catching the pass has been done. If the later applies, then the former had to have not been fulfilled. But then when does one act end and another begin? That's based on opinion / interpretation.
As I've said consistently, the issue is that the decision wholly rests on one's interpretation of whether Dez performed an "act common to the game", specifically, but not limited to, "advancing with it". There are differences of opinion on that and, since there is, can not be irrefutable evidence which is required to overturn the call. The call should've stood whether it had been ruled incomplete or caught, but in this case, caught. It's really not that hard.
BTW, I don't for a moment believe that play costs the Cowboys the win. It wasn't a TD, they still would've had to have scored. If they had, they still had to stop a one-legged Rodgers and Green Bay, which they failed to do anyway. Had they stopped them, they still had a chance so what cost them was the inability to stop GB.