It is sometimes useful to have some idea what you are talking about before you start talking. There are a number of Geneva Conventions. Among these are different ones that apply to civilians and to POWs. Two bears, since you insist that these "detainees" are not POWs, I suggest that you look at Article 6 of the civilian convention, which specifically states that Articles 3(1)(a) and (c) apply to this situation. (a) forbids cruel treatment and torture and (c) bans "outrages upon personal dignity, in particular humiliating and degrading treatment." Both the US and Iraq are signators, BTW.
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   Most of the attacks against the Iraqi civilians, and Iraqi police,
   and U.S, military; are caused by foreign fighters from Syria,
   Jordan, and assorted terrorists.

   How should they be categorized?

Two Bears