Matt Yglesias on why we need to play the blame game:
THE BLAME GAME. A brief comment on the subject of this game, which, apparently, it’s a bad idea to play. First off — it’s not a game. Assigning blame is a deadly serious matter. It’s also integral to any sort of viable social practice. The criminal justice system relies on assigning blame to various people and punishing them. So does the civil tort system, and so does the non-criminal regulatory system. So, for that matter, does any kind of coherent business or non-profit enterprise — when mistakes are made, you need to decide who’s to blame for them, and ensure that the culpable are sanctioned. If you don’t identify and punish the blameworthy, then people will have no reason to try to do their jobs correctly.
Politics is the same way. There’s a very serious principle-agent problem associated with public policy — the interests of government officials tend to diverge quite sharply from those of the citizens they’re supposed to be serving. This is why dictatorships tend, in practice, to ill-serve their citizens and be beset by corruption, malgovernment, and all kinds of other problems. In democracies we try, through elections and the ability of elected officials to fire their subordinates, to align those incentives. The way that works is that when bad things happen, people are supposed to blame someone, and then elect someone else to replace him. For that to do any good, you need to "play the blame game," which is to say find out who’s actually responsible.
I would add only that understanding who is responsible is an essential first step to learning what went wrong and why, and learning from the experience.