2 things. the more important one first:
after reading accounts of female soldiers being gang raped and tortured by members of their own platoon, after abu ghraib... i tend to think nothing is "totally unbelievable" when it comes to US military action on foreign soil, let alone secretive and covert action.
do you have any experience, however remote, with the military, soldiers, veterans, anything? if you don't, that would make you like most Americans (if you consider yourself an American, which tbf you may not). I reckon this to be a massive problem in this country - the ever growing disconnect between its civilian populace & its volunteer military, which leads judgments like this being passed by people who've no idea what they're talking about. the U.S. military these days has much higher standards & a hell of a lot more accountability than most of the people it's supposed to be fighting & dying for. that's not to say that American soldiers haven't done plenty of messed up stuff (& war is after all a very unpleasant business), but painting that as the rule rather than the exception is the grossest distortion.
aside - laying shit like Abu Ghraib solely at the military's feet is 100% ass backwards. tbs it was fucked & handled terribly after the fact but really, like most things, you're talking about policy, official & otherwise. which the military doesn't make. I don't like most of the policy any more than you do, but blaming Lynndie England or whoever is like blaming the kid on the corner slinging dime bags for America's drug problems.
perhaps not all of the US missions in Congo are of a "sensitive" or "delicate" nature? perhaps some of them require not caution or care, but ruthlessness and brutality?
sensitive/delicate = not getting caught, not delicate like a tea party. Special Forces/intelligence people w/clean records can be plenty ruthless when they need to be, w/the added advantage of being competent, reliable, not apt to, yunno, wander off & get high. oh yes & they're accountable to someone. anyway, "US missions in the Congo" is exactly what's in doubt - what were these missions? what was their goal? Prunier doesn't offer up any explanations, I suspect b/c he can't, b/c there were no missions. but I may be wrong. anyway, this particular detail seems rather a dead end.