It is an economical rule "law of supply and demand". You can not even blame capitalism for this. I mean if the Chinese workers wouldn't like to work in factories and continue to be villagers they could survive as their ancestors had lived for centuries. This is their demand to have a better life of standart to earn more money etc. Their supply is our demand and even they were not doing this some other countries would be doing like Vietnam, India, Indonesia, Turkey etc... I am not happy to be away from home, working almost 72 hours a week, etc but my demand is to gain enough money to have a better life in the future. Unless they are slaves this is their choice to work in those factories. And if there is a choise there is always opportunity cost.