The Hitler Youth thing comes as no surprise, there was an SS Division Hitler Jugend made up solely of fanaticized trigger-happy ex-Hitler Youth boys and they were actually (mostly still in their late teens) the ones responsible for the vile shooting of the Brit POWs in France 1940. Which had the Wehrmacht railing against what it called "putting fanatic children under guns and sending them to the front".
Following the (morally right and inherently patriotic) about-face of the Italians in 1943, German forces (not just SS) severely toughned up their conduct there, viewing all Italians as "traitors" (when in fact they had done what the Germans were unable to do: save their country from utter destruction). Incredibly ugly things happened there, mass shootings of interned Italian forces, bad treatment of Italian POWs, retaliatory (or just for the heck of it) massacres of the Italian civil population, it's a very dark chapter.