Just because these people are earning less than minimum wage, what makes you think you know better than them what's good for them, and that they "don't have a clue"? Why is this "blatantly obvious"? Why are they not rational actors but you are?
Given that so many people are making this choice for themselves, it feels like it's possible that there's demand for below-minimum-wage labor (otherwise, why wouldn't they go and get minimum-wage jobs?).