Ever wonder why the door in a 2 hour partition is 1-1/2 hour rated? The reason is that the code assumes there will be a “lower fuel load” for a door than for a wall. That means that there will not be any flammable furniture or building contents placed immediately in front of a door. A door will not be exposed to as intense a fire as a wall will.
That logic fails when you have a door that is no longer used. Now people will store boxes in front of it or put desks and file cabinets in front of it. Fire doors that are no longer used should be removed and replaced with rated wall when practical.