Neither defense was exactly dominating the game. The Packers punted three times. The Ravens punted once. For all practical purposes, both teams were legitimately stopped THREE times on offense. The Ravens took a knee to end the first half, and the Packers took a knee to end the game.
The Ravens turned it over on downs twice. Once at the Green Bay THREE yard line (forgoing basically three guaranteed points in the process), and once at their own 29 yard line (basically gifting the Packers an almost guaranteed 3 points before they took their first snap). This is the game management stuff, the situational management stuff, I think the staff (Harbaugh) WAY too often falls on the short end in big games, vs. better competition, etc.
Heard Sandusky defending the decision to go for two because if you get to OT and the Packers win the toss... it's paraphrasing "probably game over" because of all the defensive injuries / secondary personnel. But you could make the same argument the other way... if the Ravens win the OT toss, they had just as much chance of scoring a TD based on performance in the first 60 minutes.