The story of the Jordanian tanks is indicative. The U.S. sold some tanks to Jordan. A representative from the U.S. was sent to hand deliver the tanks and help train tank crews in their use.
He off-loaded the tanks and lined them up across a designated area at the Jordanian airport. Eventually, enlisted men straggled in to report for duty as tank crews. The U.S. rep was about to hand out user manuals for the tanks when a Jordanian officer stopped him.
"Don't bother with that," he said. "None of these men can read."
The real explanation is that, regardless of the literacy or lack thereof of the enlisted men, the officer wanted control over the knowledge.
Giving the men the manuals would mean that the men could look things up for themselves, which might contradict what the officer said and cause him to lose face. Having the officer be the source of all information and teaching means he retains face and gains status.
Having worked at a defense contractor supplying technology to the Saudis, my experience was that the officers were arrogant, egotistical, lazy and stupid. The NCOs weren't that bad.