Zumbi dos Palmares wasn't a cool dude, not at all. And Palmares was far from an utopia.
The Quilombo of Palmares had a despotic system with slaves, so yeah, they were former slaves slaving former slaves.
Also, some historians argue that Zumbi wasn't the hero of the Quilombo, instead they appoint to the former leader of the place, Ganga-Zumba, another former slave, that was assassinated. After Zumba's death Zumbi took the throne of the place.