How can there be loopholes for contractors to escape? Blackwater can get away with mowing down innocent women, children, and the elderly in Iraq. KBR and Halliburton can get away with gang rape in Iraq. Is this legal? No. There is no place on the Earth that is not subject to laws to which the U.S. is signatory and that make such behavior by contractors or anyone illegal.
The U.S. is signatory to the U.N. Universal Declaration of Human Rights.
The U.S. judiciary is just looking the other way. Attorneys in sync with the Federalist Society have been put on benches to do that very thing: Turn a blind eye to illegalities, to spin legal interpretations so the Bush-43 administration can get away with murder and all the other illegalities in which it has engaged worldwide.