I don't think your definitions are quite accurate. Terrorism is "the calculated use of violence to create a general climate of fear in a population and thereby to bring about a particular political objective." This is distinct from assassination, resistance fighting, and war, although I would argue the campaigns sold to the public as war are usually large-scale terrorism in practice.
Isolation, hate, and fear certainly do drive some vulnerable people to extreme actions, but I think the term "terrorism" is overused by people with a political agenda and political enemies.
My definitions are from the FBI - I have seen many movies about it ;D
The definitions will change, but I had to grab something. When it comes to resistance fighting, whether it is terrorism or not depends on the perspective, doesn't it?
This is because you are a Nazi....
That is a bad joke. However, this is the case today, isn't it? Terms used by people who don't really have an experience with what the true meaning is. I don't think the murder in NY of the insurance guy was terrorism, yet, they have now set a legal precedent - dangerous territory imo.
The FBI doesn't like the official definition because they are a terrorist organization. There's a reason we joke every time the FBI "foils a terrorist plot" that they were the ones who instigated it in the first place. After 9/11, they'd find the dumbest kid in the mosque and feed him propaganda and supplies. Usually they would "heroically save the day!" with much fanfare. Usually. They also instigated the Governor Whitmer kidnapping. And that's just what got publicized.