Hi everyone. In this thread I wanted to tell all of you a theory that makes an in-universe explanation for the Bat-Embargo, the reason for which many Batman rogues and allies were omitted from Justice League Unlimited. The theory states that when the Justice Lords, except Justice Lord Batman, went into the Justice League's Earth in the two-part episode "A Better World", they went to Arkham Asylum and with the heat vision of Justice Lord Superman, they lobotomized all Batman rogues, making them to became nice and harmless. However, the only rogue that they didn't lobotomize was the Joker, who was catatonic after his encounter with Ace in the episode "Wild Cards". Eventually, Joker recovered from his catatonia and the events of Return of the Joker's flashback sequence happened. If you ask why Harley wasn't lobotomized, the explanation is that she was retired from her crime life as seen in Batman and Harley Quinn, like Poison Ivy, who wasn't lobotomized as she presumably escaped before the Lords could lobotomize her like in their Fascist Earth.