All of that said, these foes are best described as insurgents or terrorists. They are willing to engage both military and civilian targets, to impersonate members of any local police or military, and are not themselves signatory to the Geneva Conventions and thus denied their protections. Their tactics involve terrorism and generally involve destabilization of a region which would basically be an insurgency against the existing power structure.
You are woefully wrong. Three main points:
1. There is no person who is not protected under the Geneva Conventions. At all. The question is how much protection. If you are a protected person under the 4th convention, you are owed additional protections. If you are not a protected person, you are treated according to one of the four buckets of treatment: non-combatant, combatant, surrendered or wounded combatant. In any case, there is no way under the Convention to hold a person indefinitely. If they are not a protected person, they must be released when hostilities are concluded. Now, you can say, "hey, we [were] occupying Iraq and Afghanistan, so the hostilities were not concluded", but if do say that, then the person is a national held by an occupying power.. which then confers to the prisoner Protected person status. And now you know why the Bush and Obama administration have created from thin-air the "unlawful" status. It does not exist, it's a legal fiction, and it's only reason to exist is to prevent the US government from treating the detainees as proper POW's or as protected persons. It is shameful.
2. Many individuals the government has treated as "unlawful combatants" are actually members of signatory countries. For example, British citizens, Saudi citizens, Egyptians, etc. When you say that they are not nationals of countries that are signatories to the conventions, it's often completely untrue.
3. There really isn't any circumstance that would permit any government from holding people without end, without charge. Either the captured men are soliders, in which case, they are POW's, and must be returned, or they are criminals, and they must be tried, or they are terrorists, and they must be tried.