Powell may be right that the ending of lockdowns would inevitably be accompanied by a rise in prices. However, this is just the latest reason the Fed has given for putting off increasing interest rates. Powell does not want to admit that the real reason the Fed will continue to keep rates low is that increasing rates will cause the federal government's interest payments to rise to unsustainable levels.
One way the Fed increases the money supply — and thus lowers interest rates — is by purchasing US Treasury securities. These purchases increase demand for US government debt, keeping government's borrowing costs low. An expansionary monetary policy thus enables increased federal spending and deficits. Since the lockdowns, the Fed has worked overtime to monetize federal debt, doubling its holdings of Treasury securities.