I think the government restricts what can be bought on things like WIC and Food Stamps, like not buying potato chips and soda and cool aid, is the fear that they will be misused, for a variety of reasons. It is a sad fact that things like obesity are rampant in poor communities because ‘junk’ food is laden with sugar and empty carbs, and the hope is by keeping things like that off the list, those using them won’t be tempted to use the stamps to buy that kind of thing,rather than more healthful things (or what they see as healthful, the cheap bread and peanut butter, for example, that is a common item is loaded with sugar and who knows what else…). Given how small food stamp benefits are, and how recipients often may not have the proper knowledge on how to create healthy meals on a small budget (we have had other threads with that, about how you can eat healthy on a low budget, but you also need both the knowledge, the will and the time to do that; take the working poor working multiple jobs, and it may just be too difficult). Having lived in low income areas, too, there are a lot of kids growing up with a parent or parents who themselves never learned to eat properly and a lot of the times their kids are eating poorly.
It is interesting when people mention immigrants, often they end up eating better (I suspect, no proof of this simply observation of shopping habits at places where a lot of modest income immigrants shop) because coming in many cases from poor countries, they learned how to eat cheaply (though if they live a place where they can do things like fish and gather fruits and such from the wild, might not work as well if they move to a city). Someone from an Asian culture, for example, likely had a diet that was mostly rice with some vegetables and little meat, and that is a relatively cheap way to eat.
The other reason the government does that is obvious, WIC and food stamp recipients often are users of medicaid (or now, the subsidized health care under Obamacare), or worse, end up in Emergency rooms for medical care that costs everyone.Given the tie between improper nutrition and illness and disease, it isn’t just moral judgement to try and keep unhealthy things off of the list, in other words. I am sure the government would like to have people in general eating healthier, they can’t force it, but it is why we have advertising and web sites about proper nutrition, attempts at documenting balanced meals (as flawed as it is, the pyramid or dinner plate), caloric and fat and salt content documented on the label, and so forth, for the very reason of the costs of bad nutrition.
Having volunteered in a food pantry and also at a food kitchen that also acted as a pantry at times, I think it is both wise not to necessarily judge what someone donates without knowing the background. I have seen people who once were using the pantry, who were in better circumstances but not exactly rich, who would donate what they could and yes, it was what they themselves bought, stuff bought at dollar stores, or scratched and dented cans, cheap bread, peanut butter, etc, but actually knowing them, it was what they had and they were literally donating when they had little themselves. On the other hand, I also have seen the other side, someone who I knew were well off, who was donating stuff that was what others have posted, stuff they obviously cleaned out their pantry with (there is nothing wrong with pickled onions, for example, but if you are donating food for people who literally have nothing, not exactly a first thought for nutritious food). To be honest, while anything is usually better than nothing, if you are going to clean out your pantry like that to make a show of donating, personally I would tell them not to bother (there is a difference between that and someone donating what they could, and that is all they had).
The real problem with food pantries is it is difficult to get the really healthy things to people, much of what is donated is packaged food like canned vegetables and meats, processed foods and so forth, because things like fresh produce and good quality bread are hard to process, plus you don’t know if the people even have the ability to store it or cook it, for that matter. Having worked with a food pantry, I kind of like the idea of donating, whether through the supermarket where they have “donate 5 bucks to feed the hungry” kind of things, or donating money to the pantry directly, they do buy in bulk, at wholesale levels, and that 5 bucks they get will likely buy a lot more and more importantly, healthier food then you could donate from what you bought retail IME.