Low paying jobs in developing economies have to be considered in the context of existing alternatives. If a Vietnamese rice farmer's son previously had only daily hours of backbreaking labor to look forward to on his father's paddies for what amounts to a dollar worth of earnings per day (only paid when they can finally sell the rice after many weeks of toiling) and then one day American McShoe Factory opens in the nearest city offering 3 dollars a day paid biweekly, this is a move up in the world. He'd willingly redirect his physical capacity for the job and trade it voluntarily for the money. Is this ideal? No, and to the labor market sensibilities of people in developed countries it could be seen as "looting" of workers but in relative terms, it's a previously unavailable, voluntarily chosen improvement for the farmer's son.
Yes, human rights have to be seriously improved in many countries and many companies offering jobs in developing markets really need to clean up their worker rights standards, but on a fundamental level, we can't simply compare a given economic change to our ideal of how things should be (because ideals are not limited by any practical constraints). We have to compare it to existing and previous alternatives.