You're completely wrong on this. The reason the Iraqis are attacking the US is because the US invaded them, with a bogus coalition of mainly puppets (Eritrea for example). There was no reason to invade them, no weapons were found and the intelligence agencies of the west all said that Iraq was not a threat. The UN voted against the invasion, 80% of the population of the world was against it, most thought it was pure imperialism.
So the Iraqis see this and think the same thing. They also see the US preparing to stay for a long time and make permanent bases. So they assume this is colonialism to get their oil and bases in the Middle East. You can argue whether it is or not, but the appearence is very convincing to them and still most of the rest of the world.
So the Iraqis will fight this and they will win because they have all the weapons they need, the US is bound by treaties and can't fight back hard enough, and eventually it will all cost too much and be politically unviable.
The only way to stop the Iraqis fighting the reconstruction is to structure it so they feel there is no threat. Typically the UN when it does this is not attacked because the people perceive the UN has no structure to be imperialist, for example in Bosnia and Kosovo.
So if the UN was running it and had a clear timetable to leave and make no permanent bases, no intention to install a puppet government, and was just interested in reconstruction then the Iraqis would have no reason to complain about it. History has shown that people don't attack this kind of occupation, and that they always attack the current kind of occupation.
Of course the US doesn't want to let the UN take things over because they haven't finished installing the puppet government yet, one which will be torn to shreds when the US has to withdraw its troops.