Supply shocks. Demand shocks. Logistics shocks. Pandemic shocks. The big recovery and reflation. You can pick one or several reasons the dispersion of prices in the inflation indices have exploded. Of course, for the mean inflation to be higher, dispersion has to be skewed to the upside. Big changes for small components in the price basket create noise and inflation volatility. It also means that high inflation could just be the skewed adjustments of prices within the selected basket of goods. As the businesses and consumers get their production and buying decisions right, inflation will recede.
Transitory inflation could be another way of saying that as skewed dispersion closes, inflation will move back to some central tendency slightly above the 2% target. This wishful thinking is less likely if we are living in a logistical congestion nightmare.
In this product congestion world, the Fed is helpless at controlling current inflation. Of course, this does not let the Fed off the hook as a cause of the problem. The Fed could use its power to slow demand in order to allow supply and logistics to normalize. Given this choice is not at all preferred, the other alternative is just saying the problem will fix itself and hope it goes away. This seems to be the current approach. Given time, logistical issues will be solved, and inflation will normalize.