Unfortunately not everyone agrees with the FBI's definition of terrorism. The FBI's definition of International terrorism depends on a list of organizations more-or-less arbitrarily assembled by politicians. Their definition of domestic terrorism is even looser.
Basically, both definitions are "violent criminal acts [waffle]". That definition is circular, because terrorism is criminal.
The word should be banned from newspapers and from political and legal discourse. Broadly speaking, it means "political activities of which we disapprove".