While the question of whether capitalism is slavery is perhaps interesting (and quite a large number of people have answered that question in the affirmative), the system where you are committed, without free consent even as that is constructed within a capitalist framework, to an arrangement where a private party rents out exclusive control of you and your labor for a period of time from the government, and compels you to labor for the benefit of that private party is very different from the “you must find a willing party to give you food, and most of them are only willing to do so for money, and most people are not willing to give you money without some exchange of value” feature of capitalism, in ways which make it fit a much less controversial understanding of slavery than any that include capitalism as a whole.