re: Words do matter.
Only recently I read that Beethoven - a revolutionary and modern composer for his day - was once described by a contemporary newspaper music critic as an aesthetic and artistic terrorist - so that word has been used and misused since at least the year 1800!
Better to describe the acts through use of nouns to define the actors sometimes, so we don't think only of an abstraction -- terror -- but of behaviors, such as child murder, torture, and arson.
maybe, but the word 'terrorism' is clear enough. It means what you describe, and more, in the pursuit of political or similar means.