It's really hard to define slavery. I don't see any difference between indentured servitude and modern student loans. If a bank is projecting your future earning potential and how risky you are when deciding whether to give you a loan in student loans, mortgages, credit card ... How is that any different from slavery? They're literally projecting if you can pay off a loan amortized over ~30 years.

The Trans-Atlantic slave trade was a very brutal form of slavery. Slavery existed in many forms throughout history and I don't think our current iteration of "employment" and lending is very different from many of slavery's historical forms