Without a doubt Atlanta screwed up - I said that. But Dallas had to do an awful lot wrong to get in that hole to begin with, and an awful lot right to get back in the game where the onside kick mattered. What the Cowboys did was huge, both on the bad side to start, and the good side thereafter, so it’s not really fair to suggest the Falcon’s mistake at the end is the only factor in the win.
Both teams make good and bad decisions throughout every game, and the winner is often who comes out on the positive side of that ledger. If the Cowboys made better decisions and better plays down the stretch than Atlanta, they did their part to earn the win and Atlanta didn’t.