John Oliver presented a very one sided view on a very complicated subject. These countries are developing. Sweatshops exist because they offer a competitive salary (often one of the best paying jobs available for people w/o skills and education). If these people weren't employed in said factories, they'd either be starving in the streets of the city or laboring in very similar conditions as subsistence farmers.

At one point in time the US was a developing country too. Every country goes through a process of industrialization, worker exploitation, and eventually, a transition to a more service-based economy. This is a long process, and it's not going to happen overnight.

This is symptomatic of a problem in the western world - we think we can solve everything. The reality is that stopping buying from these companies will not end the marginalization or exploitation of workers in these countries. They are more or less doomed to their existence. It will take trillions of dollars of foreign aid per country in order to sufficiently develop their economies to sustain standards of living similar to what Westerners deem "acceptable" (it took an estimated $2 trillion to reintegrate East Germany, it's estimated that integrating North Korea into South Korea would cost at least twice that). This money doesn't come from thin air, would likely cripple Western economies, and would not guarantee results.

Should we push for fair working conditions? Yes, no one deserves to be a slave (and these workers aren't even that). But it's idiotic to look at this only in the light of our own Western mindset. These workers have a job, are able to put food on the table, and are able to pay taxes. As the economy develops, those taxes are reinvested into communities through education. Education means that the next generation doesn't have to experience the same shit the last generation did.

All in all, it's a little more complicated than that, but I'm not attempting to explain every single in and out of the situation. I simply wanted to offer an alternative viewpoint that's much more oriented in the reality of world systems than the selective viewpoint Oliver showcased.