in order to reject a particular military action as evil, or in order even to condemn all military action as evil, it is not necessary to call it all 'terrorism.' the pentagon doesn't have to be a nest of terrorists in order to be condemned, any more than they have to be communists or serial rapists. just because 'terrorism' is a word that the authorities sometimes abuse, and just because it is the current strongest term of moral condemnation, it doesn't follow that all bad actions or death-dealing actions are terrorist. i more or less reserve the term for military-style actions intentionally directed primarily at non-military targets, at non-combatants. now i actually do condemn, say, hiroshima as state terrorism. and i actually do think there's a difference between attacking the wtc and the pentagon, even though using an airliner full of ordinary passengers to crash into the latter is also terroristic.
i don't think terrorism should be distinguished from other sorts of things by what sort of person does it (state vs. 'non-state actors') or methodologies (suicide attacks, e.g.). but i'm saying this really is a distinctive sort of demented action or person, where i set out intentionally to kill people who have nothing to do with the conflict i'm in, telling myself that i am actually prosecuting that conflict.