First it was about a video and they imprisoned the creator of the video. Destroying people is not something they worry about.
Now the video story has fallen apart (but that guy is still in jail) and congress is getting ready for hearings that will surely get headlines. Obama needs those headlines to be about something other than incompetence or worse. So a sordid affair between the CIA director and a "crazy" woman fits the bill nicely. Lots of headlines now about her, about her e-mails, about how nuts she is, about Petraeus lack of judgement.
And from now forward, anything she says will be viewed as the ravings of a lunatic. Anything Petraeus says will be viewed as self-serving attempts to shift blame for his own dreadful lack of judgement. That is if he ever says anything, which now looks doubtful.
That's why you destry this woman if you're Obama and his propaganda media.
This is the clinton mo. Make no mistake. THEIR strategy to cover their OWN guilt. ALWAYS