The AFQT is an aptitude test. It does not measure intelligence in any way. Categorizing a person with a relatively low AFQT score as a "moron" demonstrates a significant level of ignorence of this fact.

A CAT-IV enlistee (a person with a score between 10 and 30 on a 0-99 scale) may have demonstrated a low aptitude for military service based upon the four areas of the ASVAT that contribute to the score (these are Word Knowledge, Paragraph Comprehension, Arithmatic Reasoning, and Mathmatics Knowledge) but, depending upon the specialty in which he or she ends up, can contribute as much or more than another person in that specialty. As a former field artillery commander, I doubt that I'd have put a CAT-IV (or one of the CAT-Vs we had in the military in the mid-1970s) in the fire direction center, but they did fine in the ammunition resupply platoon. On the other hand, working in the data center is a better job for a higher scoring person than humping projectiles.