An older relative had a very successful small conglomerate of businesses. One of them manufactured something costing close to $100 that Wal-Mart was interested in selling in its stores. After extensive negotiations, my relative told the Wal-Mart VP no because Wal-Mart was pressuring them to use cheaper parts that would make the product wear out more quickly. Wal-Mart didn't care because they'd be able to make the sales and then consumers would come back to buy again sooner, but my relative felt that was dishonorable. The VP said it was the first time a potential supplier ever walked away from him. They are notorious for their abuse of suppliers, and the ethical concerns are often very palpable. You might suggest this is simply market forces playing out, but we decided long ago that monopoly power often leads to a market we don't want to see in this country.
We the people get to decide what kind of society we want to live in. Their monopoly power means that in so many of the rural areas where they are, they might be one of the few viable employers. When people are poor, it's not so easy to just tell them to relocate to another geographical area, so it's easier for the entities benefiting from that to maintain the status quo at the expense of others. If we decide that for Wal-Mart to stay in business in the USA they need to pay employees more, with health insurance, then so be it. If they can't, then they can just go out of business and be replaced by a company that is able to navigate that balance better, offering pretty low prices while paying a bit more in wages.