Image related is fine but it specifies Volunteers as an option in its title. Why they then kept the ball and chain I don't know.
It's mandatory for money empires as it increases the value of gold in hurrying production.

>>2074611
>>Civilization
>A 1 pop trade for production. Considered overpowered.
It also fixes unhappiness.
>>2077084
>In the modern age slavery has to carry negative connotations
I find even this is taboo because depicting slavery is the worst taboo possible. Even implied rape in story games is less taboo and that's saying something.

>>2077187
>slavery comes with potential revolution
>exporting slaves makes this worse
Africa is still slaving today but exports less to the new world and Arab world. Exporting is perhaps the best choice... if you had a higher intelligence to exploit this wealth like some kind of prescient view into the future.
Remember that the other selling point of slavery, perhaps THE point, is it deals with overpopulation.

>>2079266
Depends what is a dead weight or loss for an economy. It might surprise you to find out a lot of people are dead weight.
If it has been studied, Africa and Asia would have examples in various stages of economies relative to western ones.