That is why I suggested growing your own chocolate(or whatever). Not only will it be healthier(organic), but also it will be a way that doesn't support these kinds of abuses.
At this moment, that's all we can do. We can only be responsible for ourselves and our actions. Perhaps later in life you can actually undertake a more ambitious influence on eliminating these awful circumstances that these people who are being treated as slaves are enduring. Unless, of course, if you have that power right now, then by all means I'd say "go for it!" :)