In that context, it makes sense.
Someone crazy enough to be involved in it would be crazy enough to compartmentalize it.
Uh oh.
Are you calling me crazy too?
Remember, that's my theory. ;-)
But it's really not that crazy. If he did it out of some sort of perceived righteous motive (accurate or not), it would be immoral to target any one but the guilty. In my theory, the 'Feds' were all one. Department, age, and culpability were irrelevent, but a 'local' wasn't the bad guy.
A crazy and immoral person wouldn't make any such distinction and just blast anyone in his way.
Now please don't misconstrue what I'm going to say next. What follows is just something to think about. (While I share his outrage (if my theory is correct), I do not approve of what he did. As Claire Wolf said: "The problem with America is that it is too late to work within the system, but it's still too early to start shooting the bastards.")
Think about the various agencies housed in that (and every other federal building in this country. How many of them are constitutionally mandated? Not many. How many of them violate and restrict our God given rights or extract our money through taxation and our property through regulation under the guise of 'helping' us? Probably most of them.
If we just followed the Constitution and those unauthorized agencies didn't exist, would there have been such a horrific death toll? Or even a target? If the government wasn't out of control, would there even be the outrage that could trigger such a horrible act?
If we could only unring that bell or prevent it from ringing again.