This argument (if you want to call it that, it's more like a random thought) rests on the following assumption:
If you consider your life as the sum of your available time, then it logically follows that your current employer (quite literally) owns you(r life, since they own your time. After all, your time is all that you have and nothing more).
Both slave owner and employer are your owners. That's where the similarties end.
Slaves were judged based on their physical fitness. It was an objective processes, pure and simple.
Employees today are coerced into putting up with a myriad of bullshit/mindgames, and any semblence of fairness is thrown out the window. Nepotism, familial wealth, "likeability" often take precedent over ability to produce results. Creating a harmonic, fraternity-esque team is more important than ability. In other words, purely subjective.
I guess that's the flaw of the human condition. We (despite our strongest intentions to be efficient) are all highly fallable, beat into submission by our (sometimes conflicting) emotions.
I'm just glad I was never hired (edit: was hired, but quickly fired, thankfully), nor will I ever hire.
One man working for himself, by himself, with himself.
[After all, a team is just there so "participants" can pass around the blame.
The ultimate deference of responsibility.
It's a shame (and mystery) as to why "teamwork" is regarded with such nobility.]
addendum : if you take into account inflation throughout the past few hundred years, the disparity between the ultra ultra wealthy of today and those in poverty is HIGHER than those of Thomas Jefferson's time between slave owners and slaves (when current societal wealth gaps are taken into consideration). The value of the rations/housing that slaves received is actually MORE than the average wages of today, in this context. in a philosophical sense, the "oppressed" slaves of yore had more "wealth" than the average American of today. #perspective