Terrorist?

I have encountered more examples of the frustration aggression theory that has haunted me this semester. The article, Fighting Terrorism Can Terrorists Be Defeated Militarily, I was provided in my Political Science class, was dealing with ISIS and I was required to comment on whether terrorists can be freedom fighters. I personally see this as a yes, depending on the majority that agrees, I do not agree on the killing of their mass murders of the civilians to achieve a desired goal. ISIS sees this act as justified and would fit into the idea that violence is necessary. I realize even more how lucky we are as Americans to be part of democratic government when I read articles like this. I feel discussion would be a great start to a more efficient start to achieve desired goals, but what happens next is the bigger question.