Because we live in a society that requires a solid base of slavery to function. It always has. Base level resource extraction and processing (cocoa, cobalt, rubber, sulfur, et al.) is done with slaves in order to have an abundance of consumer items at the other end. It is not work people want to do. It is work people will only do under threat of death. It is a horrifying thought. Or it should be.

I think you are right in that it is worth discussing, but you must come at it from an honest standpoint. You can not pretend like this is some kind of aberration—it is the backbone of our capitalist society. You can not fix a systemic issue with small changes. A quarter of humans on this planet live in abject poverty. We accept this kind of inequality because "everyone is equal" is something we aspire to one day believe—currently we do not.