[NSFW] Who is the worse type of person who enslave another?

[NSFW] Every now and then, a story busts out in the media about an ongoing ghost of a crime of human trafficking. There seem to be two main forms, sex, or gain. Either the enslaved person is utilized for cheap labor to manufacture something their captors can sell or to make the labor of what they are selling cheaper, and those who enslaved for sex. A small number are enslaved just to punished, tortured, or controlled, just for kicks. Which slaver is worse, and which form of slavery dips slightly worse than the rest, since they are all bad? [NSFW]