First things first, the old phrase "wage slavery." During the time when chattel slavery existed and flourished in the United States, it was commonplace in the north to contrast the condition of slaves on southern plantations with the supposedly far superior position of wage laborers in northern factories. Socialists and other critics of capitalism coined the phrase "wage slavery" as a deliberate polemical attack. The idea, which was immediately obvious, was that the self-justifying myth of capitalist ideologists regarding the "free" marketplace concealed the reality of the bondage that industrial workers were trapped in under capitalism. The term was not an attempt to arrive at a neutral, evenhanded, objective, fair assessment of the condition of workers from what John Rawls would later call the "original position" but was intended as a slap in the face of the apologists of capitalism.
With regard to the lengthy and very helpful comment by Michael, here is his last paragraph:
" I'm not quite sure what it would look like to describe capitalism using the language of personal relationships, but I think I see it in, e.g., "Employer X is humanly decent and unobjectionable, because X demonstrates a caring attitude toward his/her/its employees"; "My boss and co-workers are family to me." I doubt this was Prof. Wolff's point, but it might be interesting nonetheless to talk about the ways in which this use of language is wrong-headed, too."
That is exactly what I had in mind in my throwaway comment at the end of my post. Marx labored long and fruitfully to disabuse his readers of this way of thinking about capitalism. Speaking technically, that is why he wrote volume 1 on the assumption that commodities exchange in proportion to their labor values. In the famous chapter "The Working Day" Marx gives us a great many examples of the ways in which capitalists seek to squeeze an extra few minutes of unpaid labor from their workers, but he is insistent that these despicable dodges play no role in the correct analysis of the structure of capitalism itself.
It is a very bad mistake to suppose that what is really wrong with America today is that not all employers are as nice as Ben and Jerry. Just as slavery cannot be understood through the lens of interpersonal relationships between slaveowners and slaves, so capitalism cannot be understood through the lens of interpersonal relationships between employers and workers.
The nice guys are also exploiters.