Not surprised. Hacking Sony is one thing. Hack the FBI and you end up in a dark room somewhere. I almost feel bad for these kids, if they are indeed kids.
They certainly act like kids. And, independent of that, I feel sorry for them. And I am nowhere near as sorry as they will be.
This wasn't the FBI, it was some other hacker who was pissed at him. The screenshots [1] show that quite clearly. That guy likely just turned xyz over to the feds after doxing him (and rooting him, and taking over most of his online accounts)
[1]
What's really funny is that going after an official FBI site would have gotten less of a backlash from real hackers. Attacking Infragard is like slapping a bunch of hackers (white-hat and black) in the face, so they're going to be a lot more motivated to expose the perpetrators. It's all pretty silly.