The truth is the Chetniks curtailed their guerilla attacks against German troops when the SS started murdering Serbian civilians in reprisal. Churchill withdrew support for the Chetniks and started supporting Tito's communists instead. Tito didn't care about Serbian civilians. Neither did Churchill apparently.
Sorry I’ve never dug that deep. I just know what B-17 crews wrote after the war. What you said sounds more like FDR and Stalin than Churchill. I worked with a B-17 navigator that flew over Germany a lot during the war. He hated FDR and Stalin. He admired and respected Churchill. All I can tell you.