The Constitution is a democratically-formed device, and the Constitution contains the 14th Amendment.
It isn't. The Federal Reserve Act, passed by Congress and signed by the President in 1913, allows the Fed to do all the things it does.
But this has no bearing on the debate around who has sovereignty over deciding things.
"That's bad, and the Fed intervening is therefore good" does not dispute its anti-democratic nature.
The Constitution is a democratically-formed device, and the Constitution contains the 14th Amendment.