I'm guessing the jihadi's promotion was the result of strings pulled by higher-ups, and the FBI not opening a case to look into his internet posts praising the fragging of US soldiers by that other jihadi, comparing suicide bombers to soldiers jumping on a grenade to save others, etc. was also the result "discouragement" from higher-ups.
I wouldn’t suspect thngs like that but finding out that such were true would not amaze me terribly.