Actually I've heard that New Balance parts are made by sweatshop labor and merely assembled in the U.S.. I don't know if this is true; New Balance denies it.
But the fact is, I doubt you can live in the U.S. without buying something created by sweatshop labor. And you certainly cannot live in a capitalist country and live exclusively on goods made without exploitation.
My feeling on this whole issue trying to be a "good" consumer is:
1) honor boycotts called by organized movements. 2) buy less exploitative goods in preference to more exploitive goods when the choice is reasonably available (reasonable being defined by your particular circumstances in life) 3) Devote the spare energy that would otherwise be spent in pursuing maximum personal purity on political battles to fight exploitation.
You cannot clothe yourselve, feed yourself or in general live on nothing but ecologically sound goods produced without racism or exploitation of workers. The fact is that atttending demonstrations, writing letters to politicians and to periodicals, and in general engaging in political activism would gain more for exploited workers than a life of monkish near purity.
Boycotts of explotive products are extremely useful -- as part of organized campaigns or even as spontaneous sources of pressure. But there is a limit to how much time and effort it is worthwhile for an individual to spend time investigating the purity of everything he or she buys.