If it really was the case that the harness is at fault here, that'd be much more terrifying, as it would imply that current frontier-adjacent open models (like K3) would be able to achieve similar ends with a custom maladapted harness.
The narrative these guys are trying to push is that the model itself could be smart and non-aligned enough to end up doing something devastating to accomplish something entirely unrelated. It's definitely not what happened here, as it always turns out to be in these cases it's much closer to Clever Hans than to a paperclip maximizer. Still they're trying to squeeze the blood from the stone to support their narrative and justify a monopoly.