We're talking about a country that has been sliding towards the edge of complete sectarian strife for the past few years, with escalating levels of violence and lines being drawn. Nevermind now hardocre fanatics form both home and abroad running amuck around the place. And wasn't one of the few things the Iraqi legislation has been capable of the dissolving of some of Saddam's actually progressive laws...?

You don’t think people should be responsible for their actions? Even children without parental supervision know the difference between right and wrong and understand that there will be consequences if they do something considered wrong. It’s hardly a cop-out to say that people should act responsibility if given a little freedom. It may be a bit presumptuous given the circumstance but hardly a cop-out.
Vous must be kidding. Regardless of what they should and ought to be doing, it is pretty much a fact that in the absence of credible enforcement people will all too often simply ignore "the rules" even in less extraordinary circumstances as have reigned in Iraq for a while now. Assuming anything else is simply naive. You said it yourself: "understand that there will be consequences if they do something considered wrong". Well, the thing is, among the many really bright things the US did was entirely dismantling all the existing institutions charged with taking care of these things and not building working new ones to fill the vacuum...

Of course people are responsible for their actions. That just isn't worth a rusty tin can full of slimy rainwater in practice if nothing exists to keep them from doing as they will to each other. Nature and human societies hate vacuums. Social power vacuums will shortly be filled, and rarely by very pleasant people. It could be argued that just about the foremost duty of any ruler is specifically to keep this from happening, in order to avoid a Hobbesian Jungle situation where, as it were, "the strong did what they could, the weak suffered what they must".

Ultimately, the whole thing traces back to the rank inability of the US to do a decent job about occupying the place. If whoever is in charge isn't doing his job right criminals, extremist groups and other such unpleasant elements will be running amuck, and this is universally regarded as a shortcoming of the ruler(s).