It causes a certain amount of unemployment, for some workers are not productive enough to warrant even this wage, but society has put into place institutions like social security to provide for these people.
In other societies, there is not sufficient development of resources to employ everyone. Each worker is needed both to support the economy and to invest in the infrastructure. Those workers that are not employed are both able to work and often have people dependent on them. If a minimum wage was set both the economy and the individual workers would suffer. Our judgment that this is "labor exploitation" is very ethnocentric. Supporting this type of "exploitation" by purchasing products in countries where labor is cheaper creates no ethical problems at all, and avoiding it would be vaingloriousness.
However, this argument does say that labor exploitation in a country that has prohibited it is wrong because it conflicts with the laws set by that society. Such exploitation is unnecessary and serves only to enrich the employer at the cost of the worker. Furthermore, it competes with societies that are trying to better themselv