Who gives a fuck about the city now that Dany? None of them have any real attachment to the city or are even from there. Why try to rule these assholes? Why try to root out the Sons of the Harpy? Loot the city's coffers, buy the ships to go back to the Westeros and enough sell-swords companies to build and unstoppable army with the rest of the Unsullied, and bounce. Shit, have the two remaining dragons put all of the Mereen to the torch and call it a day. Tell Jorah and Daario to meet across the sea after they find Dany and Drogon. Makes zero sense to stick around.