You hinted at the reasons: the work they provide is useful and they need it to provide income to their families. The system is skewed against them but it doesn

You hinted at the reasons: the work they provide is useful and they need it to provide income to their families. The system is skewed against them but it doesn't mean you have to take advantage of the lack of protective rights to abuse your power over their life. The helper I sponsor is basically free to do what she wants. She comes a few hours a week doing basic household chores. She is paid decently and is able to take holidays back home a few times a year and work for other people to increase her income.