Since the 1840s Socialists have claimed to speak for the worker, and to protect the worker from "exploitation" by business. Of course, the original socialists like Marx mostly complained about conditions that existed in pre-capitalist economies as laissez-faire economies were only in their infancy when the "Communist Manifest" was published.
Regardless, Rick Kelo asks us to consider where we see persistent & soul crushing issues of exploitation of the little guy: were they in capitalist America or in socialist USSR? In capitalist South Korea or in socialist North Korea? In capitalist West Germany or in socialist East Germany?
As Rick Kelo points out, Socialist's argument that the worker is exploited are fallacy from beginning to end because they rely on calling any existence of labor exploitation. Obviously labor exists in any type of economic system, including Socialism. The difference to Rick Kelo is that under capitalism the laborer peacefully enters into a voluntary transaction to cooperate with his fellow human being. Under socialism the laborer is forced by arbitrary dictate to provide his labor, at a below fair price, and murdered if he does not comply. Also the laborer is free to leave under capitalism & not free to leave under socialism.
If Socialists want to moralize, then they must do so by first recognizing the moral arguments are all on the side of peaceful, free cooperation - the capitalist system. There are no moral arguments favoring violent, forced coercion - the socialist system.