That's not really the point of the book (and therefore the meme). You should at least read the introduction, but basically the book explains the massive role debt has had in human history, but one theme that shows up again and again is essentially payday loans, rich people using debt as a way to justify their violent control of labor or resources while making I seem like the poor's fault. I also want to note (the book points this out in the introduction), but in modern developed countries you don't in fact always have to pay your debts. Bankruptcy is a thing, and nobody gets told to, say, sell themselves or their family into slavery to pay their mortgage.