Baron Schwartz, The Root Cause Fallacy:
That’s why the search for a root cause is usually a witch-hunt in disguise, trying to find someone or something to blame. If you think there is really a single cause, you eventually must identify a single person. If you stop short of that, everyone knows the process was a farce. But blaming a person is also a farce. Everyone knows that someone’s being thrown under the bus and that wasn’t the real problem.
“Fallacy” might be a little strong, but yes, a dysfunctional post-mortem will descend into a witch-hunt and someone can wind up on the horns without any real solutions being proposed. Not that no one ever deserves to get strummed out, but it can’t be your first reaction.