Did you forget or just not actually watch? Jack absorbed God's powers. That's how they defeated him. He became God. Why would he send them to cages when he's on their side and he's literally the new God....

That's literally exactly the opposite of what Dean wanted for Ben. When Ben asked Dean to teach him, he went off on him telling him basically HELL NO because he didn't want that life for his "son". That was a huge factor in his choice to wipe their memories of him. That and the whole, landing them in the hospital, part.