The CEO does not operate in a vacuum -- they, too, can be the victim of the circumstances they find themselves in. By saying "person X screwed up" you're making it impossible for yourself to learn important things that could prevent the same problem from occurring again. This is true regardless of the level of the person you're blaming.

The people who truly improve systems are, in my experience, the ones that do consider multiple causes of failure. The ones who latch onto narrow chains tend to fix symptoms and then think they're done.