I supported the war in Iraq and I'm not especially ashamed to admit it, though I also agree that it has been a disaster. I take the "war has been badly handled!" line, cos, like I would have done way better.
Here's an example of something that is screwed up; America has let in TWO Iraqi refugees in the past two months. I guess this is a minor point in the grand scheme of things, but I think there's something really obnoxious about that.
When they realised that there were no WMDs, America was keen to play up the liberating role of the invasion. It's more difficult to sell the humanitarian story when you do everything you can to stop people finding a new life after you destroyed their old one (or just made it worse).