Graduated from high school - from special ed classes. I would expect every recruit to be able and willing to stand at attention - to receive, understand and carry out his sergeant's orders. That's not being a Rhodes scholar, but a non-negotiable minimum.
The poor guy spent his life in special education classes and evidently only has the I.Q. to do menial tasks like empty the trash. I'm not an expert, but I think an Army scout has to be able to understand and remember complex orders and may often be in a situation requiring snap decisions. Anyone in the military should have good situational awareness and this guy did not even know there was a war going on? Someone as oblivious as that is likely to wander into trouble. I think he would have been a danger to himself and others.
Emphasis mine. Understanding orders is a matter of intelligence. Autism has nothing to do with intelligence. It can have a lot to do (negatively) with the ability to recieve and carry out (OBEY) those orders. Heck, getting the autistic person to even acknowledge that the order was issued (if the order was to do something unpleasant) could be problematic.