As much as people hate being labeled a consumer, the truth is a consumer has far more power, for the better or worse, than a voter, a citizen, or a human being. Consumerism can fuel and fix injustices around the world. When consumers inform themselves of the connections between the products they buy and the injustices in the world, they can choose to buy products that promote the world they want to see. The consumer finds a new power that can help counter the injustices around the world more effectively than any vote or law.
This is the same power that gives poor migrant workers the ability to dictate human rights terms to multinational corporation. This power has been the birth of political revolutions from the US, India to South Africa. This power forces companies to respect civil and human rights beyond any law enforce. This power can make it unprofitable to support injustices anywhere in the world, forcing powerful companies to meet a just consumer demand.
This is responsible consumerism.
Further Reading
USA Today Survey: Most would boycott irresponsible company
The Guardian: Do boycotts really work?
Harvard Business Review: When Do Company Boycotts Work?
The Responsible Consumer 