Please, it's basic labor. Today's Wal-Mart is directly analogous to yesterdays manufacturing plant. Wal-Mart shuts down all the competing businesses in an area so that it becomes the sole (or at least commands such a large amount that it can dictate terms) employer of low-skilled labor.
There's such a concept of monopoly of employment as well as monopoly of production.
And you can argue "well there are still other jobs". This is partially true, even though there are inevitably vastly less) but they all have to compete with Wal-Mart and will be forced to adopt similarly abusive practices.
This is why no one wants to live in an unregulated or even lightly regulated capitalist society: competition does not always lead towards a benefit from an overall perspective.
Two excellent examples: missile stockpiling and male walruses.
No one wants the world to have 10,000 nuclear missiles. If the US and the Soviet Union both had 100 missiles each, it'd be effectively the same balance as 5,000 missiles each- except that it would limit the destruction if WWIII every occurred. But because both parties were locked into competition and couldn't be controlled by any outside source, both parties developed stockpiles that neither really wanted.
Male walruses. Female walruses are attracted to the biggest male. Therefore the bigger you are the more mates you have. Unfortunately being a 10 foot long, 2 ton walrus is actually very bad for you. Some male walruses get so big their bones actually collapse in on themselves because they can't support the weight. It'd be better if they were all fifty percent their size and it wouldn't change the balance of competition, but it would make for some more comfortable male walruses.
No one wants to destroy main street, create an endless mire of working class poverty and make all American consumer goods worthless crap that's made in China.
But all it takes is the American publics pathological consumerism and one firm who is willing to cut any corner to create "Everyday Low Prices" and then everyone has to compete against them and everyone must adopt their practices.
This is why capitalism does not allow for choice or freedom.
Government regulation allows a degree of restriction upon the producer to allow a degree of freedom to return to the consumer and employee.
Right now we have 25 foot long 7 ton walruses that all have 10,000 missile silos on high alert, at all times.
We basically need to reboot American capitalism so that it returns to a more genuinely competitive era.