sorry deleted the orig post before i realised you'd replied.
it's a complicated argument - but when goatfucker1 is wiped out by a drone, goatfucker2 steps in cleanly and goatfuckers 3 and 4 follow loyally. by keeping goatfucker1 alive: goatfuckers 2,3, and 4 are in an uncertain situ re their chain of command. this can be manipulated into factional conflict especially when goatfucker1 re-emerges expecting their former position. in the meantime you get a period of inertia/uncertainty.
not saying that's what happened in this case, but its a silver lining to a very dark cloud.
Re vietnam: accounts mention hunting caucasians/blacks accompanying guerillas. At least three theories exist about this: first, that the rumours were just that - rumours; second, the NLF acquired advisors from the soviets or former french soldiers or; third, they were disaffected American draftees that were MIA. In any case this fell within mandate of units tasked with phoenix even if not strictly within the mission of disruption of communist political infrastructure (ratsancong) - for obvious reasons.
note: never read accounts of this elimination actually occuring, but i've certainly read reputable accounts of the contingency planning (possibly associated with AATTVN sources).