Good question my friend.
The Curley Effect: intentional destruction of a city by a politician to drive out the existing political opponent class (taxpayers; business owners; middle class) to bring in the poor and unwashed.
Thus greater control of the city.
Let criminals out. More taxpayers flee. Even more control.
Control the city entirely and the voting system = control the entire state.
Control five or six big cities giving you five or six swing states = control the country.
Thus, crime itself becomes a political “win” for Demonrats.