Earlier quoted context omitted.
Functionally there's little to no difference between what you've described and what is colloquially known as "money printing". You've essentially just redefined "money" to include U.S. treasuries and mortgage-backed securities, and then stated that it's just an asset swap and not money printing. You can use whatever terminology you want, but at the end of the day, the Federal Reserve is creating money out of thin air…
No. I think what the poster is saying is that running a government deficit is printing money. Fiscal policy is money printing, not monetary policy. This is very much not what is colloquially known as money printing, rather it's the basis of modern money theory. Monetary policy is just swapping one kind of USD denominated assets for another. It doesn't really change the size of private bank balance sheets, hence it is…
The government borrows the money from bond buyers, so that's also not printing money. (The Fed does buy these bonds, but not directly from the government because the government can't do anything with bank reserves. The Fed can only "print" bank reserves therefore it can only buy assets from banks.)