I was under the impression I was responding to the question
>> How have slaves ever historically created leverage?
They do it in all of the ways that other people do.
> Because what you just wrote sounds an awful [lot?] like a defence of slavery.
I will note that in another thread from today, https://news.ycombinator.com/item?id=14651019, you can see people speaking with approval of a company that funds training for its employees with a provision that, should they leave the company within a longish period of getting the training, they owe a large lump sum to repay the training costs. This differs in no way from a traditional contract of slavery, under which, if you want to leave your current employer, you must pay them a large lump sum.
Owing someone money if you stop working for them is in no way equivalent to being required to pay them money in order to be allowed to stop working for them.
We don't say someone who has taken out a loan is a slave to their lender. And giving that person the option to pay that loan off more efficiently via labour doesn't make it slavery.
Because what you just wrote sounds an awful like a defence of slavery.
What's awful about slavery is not the treatment of the slave. It's the fact that they are slaves in the first place.