You missed the point of my post. That good public information about nutrition is lacking especially when compared to the resources devoted to promoting unhealthy food. The resulting lack of food desert demand is then cited as proof that people don't know any better. The crux really is that it's in (almost) everyone's best interest to at least try to get people to eat healthier.
I'm not objecting to trying to get people to eat healthier. I'm objecting to blaming the stores for the problem.
It isn't a matter of moral "blame". It's a matter of accurately understanding the complex causal reality of these "food deserts", and the linked article does nothing to support your claim that consumer preferences are the root cause.
Recognizing the fact that supermarkets avoid poor areas for reasons other than demand doesn't mean you have to lay moral blame on the stores. Some factors that lead stores to avoid poor areas include:
1. The uneven flow of business due to the once-a-month "income" (food stamps) of many of their customers. It is harder for stores to operate and cover work shifts when 80% of the demand is in the first week of the month
2. Higher insurance and security costs, due to higher crime in the area
3. Fewer available employees with needed skills, thus requiring more training
4. Long term uncertainty regarding the economics of the area. Building a supermarket is costly turning any profit requires several years of operation. Poor areas often undergo drastic changes that can undermine a supermarkets customer base.
These are all legit concerns that make Supermarket's hesitant to build in poor areas, and as such, show that the "free market" is not capable of solving this problem. Yet, it is also not the fault of most of the residents who live there and desire more healthy options (or would desire such options had they not been conditioned by growing up without such options).
Factors outside their control lead to lack of affordable healthy food options, so they have a less healthy diet and more health problems.
Its just another way that being poor is very costly and leads to countless obstacles to positive future outcomes that people who grow up with more wealth do not face.
IOW, it isn't about "blaming" the stores, but about not blaming the poor diet of poor people on some absurd notion of their magical free-will choice to eat less healthy that is unrestrained by the environments in which they exist.