And a lot of these families know this or even get healthy food for free but still choose unhealthy food.

This is 100% true for the poor, uneducated, and/or blue-collar members of my family (which is the majority of my family). They just don't seem to have the palates for better food. Even the ones who work part-time at the big box store because that's the only job around: they have plenty of time to cook healthier meals but they won't do it unless it's a big holiday or they're hosting a get-together (that is to say, they know how to cook well but avoid doing it). If Cheryl is hosting poker night at her trailer tonight, they'll drive into town to pick up beer and smokes, but they won't make the same drive to buy ingredients for homemade food for their kids.