The article fills in a little of the background to the massacres starting in October 1965. A little earlier, in mid-1965, "an attempted coup by leftwing army officers and, secretly, by agents of the PKI, in which seven generals were murdered,..."

The article doesn't say how many generals Indonesia had before the attempted coup. Obviously seven fewer after the attempted coup. I wonder what the surviving generals thought of the recent murders of their colleagues?

The article is written as though the surviving generals sat around afterwards waiting for Britain to incite them to mount a response. That seems unlikely. It would be more usual for the surviving generals to take the murders of their colleagues personally and to attempt a response on a kill-or-be-killed basis, without waiting for British incitement to rouse them to action.