The cost is and isn't the point.
A poor parent is trying to solve a problem with affordable name brand junk. The problem they have is one that a MC parent doesn't need to solve.
Both MC and poor parents do what they do out of love. In the case of the poor parent, the junk says, 'I am meeting your needs on one level. I am doing this out of love'. The MC parent offering organic steamed kale is also saying, 'I am meeting your needs on one level. I am doing this out of love'. Both parents are trying to feel adequate in their own circumstances. We need to respect the loving intentions.
The glib narratives surrounding poverty are the fuel for a certain political message. It's very easy to fall into a trap of assumptions, given how this message intentionally plays on so many of our worst instincts, that the poor are ignorant of good nutrition, or lazy, or disorganised. It's a short hop from scurrilous headlines to, 'Why should people like us pay for these lazy scroungers to feed their children junk?'
Yes, there are people with personal shortcomings who bounce from emergency to emergency and their children suffer. But mostly there are people who simply don't have enough money to ever see their way out and up from their inadequate home in a depressing area, either in terms of imagining a long term future or in terms of any single special occasion to look forward to. All the big occasions - Christmas, summer holiday, birthdays, going to school and providing uniform, shoes, bags - involve expense and stress and the underlining of financial difficulty. All the long term aspirations require sufficient income to support planning.
Poor people are not stupid to the point where they don't understand the reality of their own situation.