I think the main reason the FBI got involved was not because the leak was massive or damaging, but to figure out whether he actually broke any laws. Or more realistically, to find <i>something</i> to charge him with.
I think that the best idea of what the security group did was comparable to calling up a company that does not provide a directory and the group showed you can easily create that directory but didn't publish it
From the educational documentary Hackers:<p><pre><code> JOEY
That was me. That was me. I did that.
DADE
You did this from your house.
Joey takes a drag from his cigarette and just
nods, with a big grin on his face.
PHREAK
What are you, stoned or stupid? You don't
hack a bank across state lines from your
house, you'll get nailed by the FBI. Where
are your brains, in your ass? Don't you know
anything?
CEREAL
Stupid, man. It's universally stupid.</code></pre>
Wow. He's crazy, loves God and Fred Phelps.<p><a href="http://www.queerty.com/andrew-auernheimer-saved-your-ipad-from-atts-security-flaw-he-also-loves-fred-phelps-20100618/" rel="nofollow">http://www.queerty.com/andrew-auernheimer-saved-your-ipad-fr...</a>