[defrost]

The country that landed men on the moon adopted the metric systems as the basis of its measures before most other countries and programmed its moon landing systems using metric.

The country is a metric country (see: Official definition of the US foot).

Its citizens, however, largely still roll coal measured by chains to the hogshead.

[rainbowzootsuit]

The previous moon thing is a joke and at least partially an explanation for "freedom units," which is a joking (I think) commentary about the citizenry's beliefs about "their freedoms," and somehow these freedoms translates to freedom from using the metric system when they roll coal along a couple furlongs of interstate (in a truck that contains only metric fasteners.)