All fascisms involve the identification and elimination of undesireables. Power is the method by which that is accomplished, and nationalism is only a symptom of this force in operation.
you have it backwards. if governments that identify and eliminate undesirables are fascist then pretty much every government in history has been fascist.
ie, all men are mortal, but not all mortals are men.
I don't think of fascism as a state of being so much as a tendency, so yeah, choosing to recognize someone as undesirable is a fascistic tendency designed to disallow someone their freedom of being and/or thought. Throughout history different fascistic societies have sought to eliminate people of all schools of thought, free-thinkers and status-quo'ers alike, which while maybe too abstract an explanation in this context, helps illustrate how designating a terrorist or a "leader of Al Qaeda" is neither a self-evident logic nor an unquestionable act. History tells us that the more important a particular undesirable is to the acts of a government, it reveals actual weaknesses in the society that invests that government with its power.