A person can only be said to be committing terrorism if they are able to embody this ideal, that is to participate in some sort of campaign against civilians that is of such a magnitude that it actually does cause them to live in terror and to change their way of life as a result. If this is the case, then we should not be so eager to use the word "terrorist" because it implies the existence of such a campaign. In reality, these campaigns are sad, weak, and ineffective. Their participants are all similarly deluded, whether they are blowing themselves up, opening fire on civilians, or doing some other sort of stupid activity. Thus, we should not be calling these participants "terrorists" but rather "wanna be terrorists".
The reality of effective terrorism is that it must arise through a power vacuum that rarely exists in the developed world. Terrorism is really a story of radical groups operating in failed states, oppressive dictators, and of course western corporate sponsorship of violent groups that oppose the peaceful organization of labor. Therefore, our response to and use of the term "Terrorism" shows the lack of understanding that the Average westerner has of conditions outside of the West.
Following the 9/11/2001 "terrorist" attack in New York, President Bush and other western political leaders exploited this lack of knowledge to create the modern ideological "war on terror". This is nothing but a meaningless show, a quixotic pursuit of only the small and insignificant outgrowths of (manifestly ineffective) anti-western violence amid the sea of power struggle in underdeveloped regions where terrorism of all types actually occurs. The objective of preventing terror in these regions is, in fact, a noble goal, but it will only prevent violence against the West if it is true that a properly organized and empowered government in such a region would be a western ally - something that is not likely considering the history of western involvement in such regions. In this context, the western policy goal of promoting democracy in these regions is not itself misguided, but the stated political goal of preventing attacks against the West is certainly a lie.
Of course, the means by which democracy is allegedly being promoted in these regions is not a means of bringing about democracy at all. Here, a mix of sinister motive and pure ignorance reigns. The motive is sinister in the sense that wherever popular sentiment is anti-western, a true democratic process cannot be allowed to occur, because then anti-western leaders will be elected. The motive is ignorant in the sense that the western leaders are generally ignorant of the actual economic, legal, and social conditions that must be cultivated in order to bring about a prosperous society. President Bush was the exemplar of both the sinister motive and pure ignorance.
Rhetorically, the language that terrorism is wrong is a pointless endeavor because terrorism arises from a political conflict. The very nature of political conflicts is for individuals to hide factual disagreements behind ideological positions. These ideological positions involve accusations of injustice. Thus, arbitrary ideological disagreements prevent, in general, the comparison of ethical positions in a way that allows disputes to be resolved.
The only meaningful way to fight terrorism with rhetoric is to characterize it as pathetic and ineffective. This will dissuade individuals from participating because they will feel it is an inefficient use of resources, and seek alternative means of bringing about their policy goals. Conversely, the more wildly overstated the magnitude of a terrorist incident is, the more media attention it receives, and the more disproportionate the western response, the greater the likelihood that some other idiot will take up arms against the West.