I never like the words expressions "freedom fighters" or "terrorist". They both try to load the scales in advance of looking at what the people involved actually do.
All war involves terror as a method - but what is pevculiarly horrible is the use of terror against civilians, and that is probably the best definition of terrorism, the deliberate targetting of non-combatants. And in modern war civiians make up the overwhelming majority of casualties.
Terrorism in that sense is is not in any way restricted to paramilitary organisations. Aerial bombardment of civilians, destruction of communities by shelling or bulldozers, internment, torture and execution of hostages, assassinations - these are all terror tactics, and they are used by states all over the world, including those who are loudest in their condemnation of "terrorism".
And the enemy should be terrorism in all its forms, ruling out any posibility of the type of response which would involve terrorism. This could provide us with anm opportunity to see where meeting terror with greater terror it has got us, and reject it for ever.
But I'm not optimistic or naive enough to believe it will work out that way.