Ah, my mistake. I thought it meant that the victims were not individually predictable, like "won't someone rid me of these meddling Anglicans" and then a bunch of random Anglicans get killed, but as you suggest, Wikipedia says " Stochastic terrorism...describe[s] a mass-mediated process in which hostile public rhetoric, repeated and amplified across communication platforms, elevates the statistical risk of ideologically motivated violence by unknown individuals, even without direct coordination or explicit orders. "