At best the FBI decided it was more important to catch these people than it was to prevent the leaking of some cc's.
According to wiki, "He later turned informant for the FBI, working with the agency for over ten months to aid them in identifying other hackers from Lulzsec and related groups"
The CIA's website went down June 15th, 2011 (towards the end of the LulzSec campaign) - definitely while Sabu was working for the FBI.
"I've had it just about up to here with inane conspiracy theories about every corner of government including the DMV and the Census Bureau, but please do give me one more!"
Edit: link to old discussion here since this his hard for some people to grasp and make the connections: https://news.ycombinator.com/item?id=2659326