You don't seem to understand my point. I live by the area, so have a clue about how & why it's a "food desert". There is no "local wiki mart" in that area, and the nearest one is just a block from a real grocery store; if you can get to one, you can get to the other. There's not enough population density to support a walk/bike infrastructure that's meaningfully different from existing roads, nor enough customers within the defined range of a grocery store to support one with a walking/biking population. If "you find yourself with a minor disability" you wouldn't be walking or biking there anyway, you'll either drive yourself (you wouldn't live in that area without a car) or get a ride from someone else (if you don't have a car, that doesn't stop practically everyone else around you from having one - this isn't a no-car area). It's a 5 minute drive from the farthest point on that map's "food desert" (in zip code 30040) to a Publix, Super Walmart, Super Target, Ingles, Kroger, Sprouts, and a dozen varying ethnic/local specialty groceries. Drive by the poorest communities and you'll see a car next to every home.
Please understand: in a large portion of the USA, not having a car isn't an option. That's not because of any intentional malice, it's just that grocery stores need a certain volume of customers to be viable, and the population density is low enough that walking/biking is absolutely not an option (no matter how good the infrastructure, for which there isn't the necessary tax base anyway). The infrastructures Europeans & many Orientals take for granted are only possible precisely because of the high population densities and limited quasi-urban distances. Here in the USA, outside [sub]urban areas we're really spread out, not congregating in villages that make local grocery stores & walking paths viable.