The word terrorist is just a derogatory word for a non-sponsered armed force. Whether a group iis classed a terrorist is down to the mind of the speaker, nothing more. It has little to do with who they kill as 'terrorist' was used by every government affected by this 'illegal army' no matter the cause or goals. Terrorism can of course be carried outr by official armies, infact that's where the phrase was first coined, during WWII by Bomber Harris describing his RAF Bomber Command. This has been forgotten lately.

One mans terrorist IS another's freedom fighter. If you fail to understand or believe that fact then you have never been in a situation that required your people to act in such a way. Usually poor peoples, with unequal rights to the opposition, with backed-up frustrations, with little resources but with a cause so important volunteers, unpaid, are willing to fight and die for the belief. Not all guerrilla warfare and illegal armies are the same & all must be treated on their own merits. You cannot Log them all as 'terorist' and vis a vis 'evil'. If only it were that simple.