Often called
terrorists by those who oppose them the relative value between freedom fighters and terrorists is a very physical and real thing.
A freedom fighter is distinct from a terrorist not in any political, theoretical or moral sense but by benefit of the support of the local population in their cause.
Thus freedom fighters are an armed group who seek to overthrow an existing power or state by force with the popular support of the people of that state. What they are said to be revolting against is not part of what defines them as freedom fighters but merely their political ideology.