The purpose of raising rates is to prevent an over-heating economy from causing inflation-producing shortages. If you know that the cause of inflation is not an over-heating economy, why would you raise interest rates? The Fed’s failure to recognize temporary, transient causes for inflation resulted in recessions in 1982, 1991 and 2001. (Also, the Fed refused to see a developing crisis in 2007; forcing banks to make bad loans in order to be able to make good loans certainly made this recession far, far worse.)
Interest rates need to be larger than inflation.