I don't have a lot of background in this, so tell me if I'm off-base. Israel is occupying land that it took from Palestine, is it not? I don't feel that terrorism is the correct term for attacks on an occupying force.
Yeah, typically if you agree with them they are "freedom fighters" if you don't they're "terrorists".
In my opinion, most long running conflicts tend to have both sides doing terrible things over the course of the conflict, so its rare there is one side that is "good" and one that is "evil".
9/11 didn't happen out of the blue, it was a response to american foreign policy in the middle east.
The troubles didn't happen because the IRA thought British rule was legitimate
Etc.
The vast majority of terrorism is because one group is controlling a region that the other group thinks they should not.