If these reports are to be believed, Sabu was working on an FBI-provided laptop with direct 24-hour FBI surveillance of everything he was doing when he hacked Stratfor and dumped their emails to Wikileaks. Other parts of Anonymous disowned Sabu afterwards (see pastebin) for attacking Stratfor, which they considered a news organization and off limits.
The Stratfor leak involved almost 1M email addresses and ~100K credit card numbers. A lot of them are said to be bigshots in DC military/security circles.
I believe the word you are looking for is "incompetence".
Our law enforcement organizations spend years and millions of dollars to infiltrate, track down, and bring to justice criminals. Who do they target? Organized crime? Hostile foreign nations? Fraudsters? Nope, they go after lulzsec and IP "pirates". I don't have a ton of sympathy for either lulzsec or kim dotcom but I can't help but feel that the FBI et al are screwing the pooch here and arresting the moral equivalent of pot dealers while the true terrorists and mobsters go free.
Anonymous/Lulz was/is the biggest hacking group ever. They were hacking businesses, law enforcement, media, websites of the US Congress and the CIA (just to name a few).
I really doubt that one could describe a plausible ranking system of law enforcement priorities that wouldn't direct real resources at Anon/Lulz in 2011.