Premise: It is a contraction of gung-yeh ho-dzo , `industrial cooperation, 'and it caught on because it is easy to pronounce, as in 'Nam or the States .  'Nam by itself is no more derogatory or misleading than shortening airplane or telephone or gung-ho .

Hypothesis: The abbreviation, 'Nam, became popular because it is easy to pronounce. 
Relation: entailment