The American argument isn't complete rubbish. Labour stands are terrible in many countries. But perhaps it's worth asking what would happen to people if labour protection measures were enforced. Many working children in developing countries would find their only livelihoods killed off immediately. The same questions and issues apply to the environment.
Trade does affect the distribution of income.
Even though trade is generally good - it is unlikely to be good for everyone. Inefficient producers find they lose their market share when faced with cheaper foreign imports. But consumers gain significantly if they can purchase goods more cheaply than before. Different sectors of the economies, the rich and the poor within countries and different countries are all affected by trade. Some will gain, some lose.