Just throwing this out there-- If some act or another is a war crime when committed by the soldiers of a nation-state, then its a war crime when committed by members of 'resistance' movements and other guerilla forces. International law and treaty law is very clear on this.

Further, there is not now, there never has been, and there never will be a 'they did it first' defense to war crimes. And reciprocity is not and enforcement mechanism of the laws of land warfare either.