A few thoughts.

1) the insulation requirement is only for exposed floors - i.e. floors with the underside exposed to the outdoors. Not "ALL the floors of the building"
2) it's not a new requirement - ASHRAE 90.1 -2004 also required insulation, although the requirements have been slightly increased.
3) insulation in these areas will reduce your loads, and save energy - that's why they are in the Standard.