Why? Because at least some Poles were throwing food and clothing over the wall, before the Germans starved them as well.
Unless you've talked to someone who survived WWII inside Poland, it's really hard to imagine the hell on earth the Germans created.
Lodz Ghetto was notorious for their leader, Chaim Rumkowski. The story is, when he was himself shipped to Auschwitz, the Jews got to him, before the Germans did.