It's basically an argument in favor of trade protectionism at the local level. To be fair, it's not a bad idea, nor is trade protectionism as dirty a word as economists make it seem.
The unfortunate truth is that free trade naturally results in income/wealth inequality, on individual and geographic levels, because it highly incentivizes economies of scale. Rather than 30 different widget makers selling widgets at $5 each, you get one widget maker selling widgets at $4.80 each, because it's more efficient (less overhead per widget). Everybody gets more/cheaper widgets, but the communities containing those other 29 widget makers may lose significant portions of the money coming into their communities - while the community with the remaining widget maker becomes wealthier than ever. And instead of 30 small business owners becoming wealthy, you may get one extremely wealthy widget business owner along with slightly wealthier stockholders.
When this happens to all industries all at once, it increases mean economic wellbeing, but decreases median economic wellbeing - and because goods become more efficient to produce due to economies of scale, it also puts downward pressure on wage labor, increases public spending on social assistance, etc.
That mostly applies to industry as opposed to retail, but to me that's the other half of the story: most communities aren't able to keep bringing as much into their community because of the consolidation/outsourcing of industry. And then the corporate retailer model increases the rate at which money leaves the community too.
I know someone who took a couple introductory economics courses will want to chime in "but trade makes everybody better off on average, because it allows economic participants to specialize at what they're already good at". But in the real world, when someone loses their job or small business due to big-industry consolidation/competition, they may no longer be able to get a job doing what they used to do, because now less people are needed to do that job, as it was made more efficient. So now they need retraining, or they go on social assistance - and the cost of that retraining or social assistance may not outweigh the economic benefits of consolidation.
Perhaps the solution to an individual is to move, but that can cause a community to enter a death spiral if enough people leave and the cost-per-person of public services increase. The community needs investment so that a new industry can bring in money, but if all the small businesses died, there may not be local investors with capital to invest, and bigger investors may not see investment in a new industry in small community as optimal because there aren't enough people able to work in that industry - a chicken/egg problem.
I'm not arguing that trade itself is bad, but it's not the unequivocal good that many perceive it to be. There are externalized costs and negative butterfly effects that can come from the type of consolidation that free trade enables - and those are harshest at the local level. Sure, widgets may be cheaper, and on average (mean) the economy improves (assuming the externalized costs are less than the improvement in efficiency - which they may not be). But that improvement means little if the resulting wealth/income go to a small number of people, with many more people losing their smaller amounts of wealth/income, all so people could save $0.20 on a widget.