^^That chart is incorrect. TN taxes groceries. In recent years it has lowered the tax on groceries to 5% I think? But, they are still taxing unless something changed very very recently. Each county can impose more tax above the state sales tax. I think Shelby county, where I lived, still charges 7.5% tax on groceries, more or less.
Southern states tend to tax groceries, or maybe it’s red states? There are exceptions of course. Most Democrats see it as regressive and harming the poor unfairly.