Do you think western manufacturing workers have a right to their relatively luxurious lifestyle even if maintaining those jobs in the west doom countless millions in developing countries to a life of hard to imagine levels of deprivation, struggle and pain?
Come on, this is ridiculous. The cost savings are based primarily on a dramatically lower cost of living, differences in exchange rates, etc. If I can hire someone in NYC for $125 / hr or hire someone in Arkansas for $50 / hr and the Arkansas guy has a higher standard of living in Arkansas, how am I exploiting him? It's no different on an international level.
But the ethical evaluation of labor practices is not as simple evaluating an improvement in standard of living. There is a line that can be crossed - the line certainly isn't crossed in your NYC vs. Arkansas example, but it /can/ be crossed (min age, min wage, max hours, safety, etc.).
I've spent time in poor countries. It's not that simple.
Though I agree that it's a bad thing for Americans that manufacturing is happening less in the States.