obama to ask for debt limit hike says treasury, page-16

"they now only display the "core" CPI / Inflation figures that remove both of these."

The USA displays both headline and core inflation. If you choose to use headling then that is your choice. The reason they exclude in addition to the volatility that comes from speculation is that increases in the prices of oil & soft commodities is cost push inflation.

Either way the long term average including commodities is 3.5%, year on year to november the US inflation is 3.4%.

All spikes above 3.5% have corresponded with speculation in commodities which has obviously since subsided eg. Oil during Libya/Egypt, Coffee during QE. All of which show that US monetary policy should not be dictated by short term speculation in commodities, thus the use of core inflation.