Doesn't take much to figure out why they use the term, either. Calling it a 'war' implies that it has two sides, and isn't just a million little murders. Calling it a 'war' implies that the oppressed, the victims, are fighting back in violent ways. Calling it a 'war' all so often implies that it can be, at all, justified.
And if there's one thing these ghouls adore, it's self-justification.