It all depends on how yo look at it, but then, doesn't everything?
I'm not going to bother arguing if the reasons we went into Iraq are valid (that is a whole 'nother thing). We did go to war, some time back, so arguing in present time if we should have or not is moot.
There are similarities between the current war and WW2, as well as huge differences. The rebuilding of Iraq is due to the similarities, not the differences.
As in WW2, we went to war to effect what is today called "regime change". To do that we had to destroy their military capacity. In order to destroy their military capacity we destroyed both their military in direct combat, and the civilian infrastructure, to prevent them from being able to create and move military useful material.
We went to war with the political leadership of those nations, not the average ordinary citizen. The Iraqi goatherder, the German farmer, the Japanese fisherman, they were not the enemy we fought against. Although great numbers of them were caught in the middle, and suffered as a result, they were not the "enemy". They were "innocents". And being the people we are (or at least claim to be) we did (and are doing) what we can to repair the damage done to the nations of innocents after we remove the "guilty" from power.
And in so doing, we prove to the world, and especially to those innocent people caught in the struggle that they were not our enemies.
The devil is in the details, and you have a valid right to argue about how we go about rebuilding nations shattered by a war we were involved in, but not whether or not we should do it. It is our moral duty to help where we had to cause harm. That is one of the things that gives us the moral high ground. The principle is valid, and proven to work. How well we do it (how much, and where we spend), and how well it works for us is open to debate. How much, and what kind of return we eventually realize on our "investment" is also open to debate, only history will eventually total up the balance sheet, maybe not in our lifetime.
I think it entirely reasonable that a functioning Iraq pay us back for what we spend on their behalf, as they can, from their revenues in oil or whatever currency they have, but I'm not going to hold my breath. OF all the nations that recieved US aid during WW2, only Iceland, (and I believe Finland) ever actually repaid that debt in cash.
We may never get "our money's worth" from Iraq, but one thing is certain, if we don't spend the effort and money, we won't get anything from them except trouble in the future.