It's not even in the same ballpark. Have issues with you employer? you can quit and find a new job. For people who aren't limited by education, skilled labor, or criminal records. Aka white collar workers making 50-80k+, they usually put themselves in situations where they call it slavery. Lack of control on spending habits, living above means, and ultimately living paycheck to paycheck and saying modern work-life is slavery. You make significantly more than a single mom of 2 kids with 3 min wage jobs, yet are struggling in the same boat? No one to blame but yourself.
If you were a slave that wouldn't be happening, and if your slave owner wanted to rape you, he or she could do that and you had no say, and you got punished for even bringing it up. Legally you are fucked too, a 3rd class citizen.
If we are talking about child labor and sweatshops overseas they might have a point, but Joe or Karen working for an agency or bank in North America isn't slavery