Sounds like the old broken windows theory, where a "messy" neighborhood sends undesirable signals about how much the people in it care for the public benefit. But a dollar store is not a neighborhood that's collectively taken care of; it's literally just a store.
I'm amazed that they managed to write several thousand words on the topic, while managing to avoid using the words "broken windows".
I have a few near me in my average suburban neighborhood and I've never heard of any shooting, and a search of local crime blotters and newspapers doesn't turn up anything either. In the entire state I found roughly 1 robber per year over the past few years. Convenience stores with many fewer locations get hit more than that, but I don't think they cause violent crime.
Possibly because otherwise the rationale seems pretty thin: Dollar stores are to blame for shootings and crime in their vicinity or the store itself because they're understaffed and messy? Not very convincing.
Where's the comparative statistical analysis of retail-related shootings for other stores, with controls for area crime rates and local socioeconomics or other confounding variables? Where is just about any hard data? It's all opinion narrative interwoven with tragic anecdotes and an occasional reference to research that might vaguely apply if you squint hard enough. Really a bad piece.
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As a side note, dollar stores seem to fill a useful niche in the retail ecosystem. They purchase mass quantities of product, much of which might otherwise end up in landfills, and sell it on for cheap prices to people who will use it. (Though some items-- not all-- are made specifically for sale in their stores at smaller quantities that are actually higher on a per-unit basis)