Yes. More specifically "by individuals overwhelmed by their work.". I don't assume she's speaking of herself there, though it's covert enough not to downright blame her employees. Employees she won't bring to her new department.
So I really don't arrive at your conclusion. If you're leading others (and what politician isn't?), it's perfectly possible that people under you screw up or are up to no good. It doesn't relieve you of your responsibilities, but whether or not she is guilty is really what the investigation is to point out.
I guess we operate under different definitions of incompetence then, which is fair, to me a leader who allows the people working under them to makes errors of this magnitude has shown incompetency as a leader.