Actually true "terror" is never justify. But here you have to distinguish the difference between "terror" and "freedom fighters". Not all terrorists are freedom fighters and not all freedom fighters are terrorist. I'm also sure the people that we bomb their schools and houses and kill their brothers and sisters in Afghanistan, Serbia and Iraq probably also view us as "terrorists".
"When fascism comes to America, it will be wrapped in the flag and carrying a cross." - Sinclair Lewis
"Those Who Would Sacrifice Liberty for Security Deserve Neither." -Benjamin Franklin