In essence, the Secretary was sticking to the March version of reality: Saddam is at the center of the war on terror, his regime is enormously dangerous, terror can be defeated through military force, and the US has an international mandate to pre-emptively invade with that military force to disarm Iraq. Further, his version of how things are going on the ground seems to be roughly what we were told to expect--not what's actually happening. Welcome--again--to bizarro world.
It seems clear that all rationales used to justify the war were inaccurate. Whether or not they were mendacious is almost beside the point. We now know that 1) Saddam was on the distant fringe of terror, not its center; 2) Iraq was harmless; 3) terror networks were energized and Iraq has now become the nexus of terrorist activity; and 4) the international community is growing ever more opposed to US bumbling in the region. (On this last point, we might observe that the other country employing the Bush Doctrine--Israel--is having as little success as the US and is as violently opposed by the world.)
As to the reconstruction, Rumsfeld's mystifying blindness is, of course, at the heart of the problem. US arrogance and incompetence are but components in the larger problem: the administration's failure to question its own assumptions or policies. Rather than revise assumptions and change course, this administration would rather try to revise history (even as it plays out). It's no wonder that the rest of the world is incensed by our policies; at what point does the willful act of denying reality incense America?
Rumsfeld's words should be a clarion call that this administration isn't going to change course, isn't going to question it's assumptions, and isn't going to see the situation for what it is. Time to fire up the incense?