Forcing someone to work for you isn't allowed, but paying someone to work for money so he doesn't starve is totally accepted.
This reminds me of this :

Working 9-5 day job with the same boring routine and for others to make them rich just to get a part of it with all the burden is for sure most distrubing form of modern slavery.We thought slavery was past concept but the system never removed it but just developed new ways of it which still many don't understand.