Notice that I gave you two examples. There are numerous other instances, go see for yourself. I'm not your research assistant. He is only a citizen until a judge decides otherwise. They may treat him like a citizen now, but his sentence could well be the revokation of citizenship. IMO that's exactly what it should be. He should never be permitted to step foot in America again.
I believe that you must enlist in the army of a foreign state (Isreal exempted for political reasons) to lose your citizenship. Walker joined a criminal organization, not the Afghan army, or our govt' would be treating all the "detainees" at Gitmo as POWs.
Our gov't would never want it both ways...Nope, not here in the good ol USA. We ALWAYS abide by the law.