"Most of the time that's price fixing and is illegal."
Bingo!
That's the answer, the fed funds rate is a price fixing tool. Banks via the federal reserve governors meet to decide the base interest rate from which most other interest rates are derived. Aka the "price" of money. This is done to optimize the rent seeking activity of loans. The banks want to optimize how much interest they extract from the productive economy without harming it to the degree it stops growing or shrinks.
Related, most people think the Fed IS the government but it is not... it's banks... https://www.stlouisfed.org/in-plain-english/who-owns-the-fed...