The very definition of terrorism is the use of violence against innocent people chosen BECAUSE they are innocent and with the idea that by terrorizing people at random, an entire populace can be intimidated into accepting the political positions of the perpetrators.
While this action might not rise to the level of terrorism, it displays the same mindset -- that by irritating the living daylights out of people who have nothing to with the grievance, an entire population will eventually capitulate to the demands of those using this tactic.
This almost like an IQ test here, folks. Goodness, gracious, if your next-door neighbor runs his car over your petunias, are you then justified when you run across the street and kick that person's dog?
Sheesh.