Just to clarify for the rest; the borrower (ECB) is literally printing new money every time they give out a loan.
If you deposit $100 with bank A, and they give a loan for $80 to person B, you have $100 to spend and person B has $80, so $180 can float through the economy.
The $80 debt should cancel out person B's surplus, but it kind of doesn't if interest rates are low enough because they'll never actually pay it back.
That's my potentially poor understanding of it.