Terrorists are only able to invoke terror if they have an possibility to dominate and control the society in which the violence occurs or degrade the public to the point it fails.
Marxists invoked terror in the general cultures of the nations in which they operated because their actions were prescriptions which have overthrown many governments. This is not a secret, and in nations with large numbers of exploited labour, this is entirely and famously possible.
Without this possibility, there is no terror and the word is invoked flaccid. Public violence is a description of events which invoke the memory of public movement, in which none exist, silently demanding a revolution to ones self and in the heads of people, isolated and murderous. School shootings or armed rampage, the detonation of a bomb here or murder elsewhere are best understood of the actions of displaced suicide. We experience no terror, just despair at the actions of the disquietists.