These guns for hire are not just a problem in Iraq, they are a problem in Afghanistan, where authorities are clamping down on unlicensed, incompetent, and excessively violent security contractors.
Two of the main problems are the US and UK, where many of these firms are based, and which have not signed the International Convention against the Recruitment, Use, Financing and Training of Mercenaries, which is why all the companies we hear about are from the US and UK.
Contact your congressman about getting the us to ratify this convention.