The claim in question seems to point to relativism: the view that every perspective has equal weight and should be regarded as equally true. Indeed, the phenomenon of cultural relativism might be invoked to argue that what might be considered to be terrorist in one setting might be regarded as normative, right and just in another.
However, the idea of appointing an objective definition of terrorism seems quite problematic, for it involves appealing to values that are not indexed to any perspective at all. Any claim on so-called ‘terrorism’ must take place from the viewpoint of some normative orientation—to do otherwise would be to ignore the historical and cultural processes that have shaped the emergence of this particular discourse, processes that have involved a consistent struggle for power over the centuries. By particular academic and popular standards today, British imperialism or slavery in America are regarded retrospectively as being abhorrent practices. Indeed, the usurping of the lands of Indians by the new colonists could also, equally, be regarded as acts of terror.
What is common about each of these events is the particular conviction in some set of ideals, such that there is a belief in the rightness or truth of a particular cause, and indeed the view that any opposition to this cause must be smashed. Where this aggression is directed in ways that are considered to be unacceptable within the conversations surrounding particular norms, Hiroshima is glossed over whilst 9/11 is bewailed.
Thus, it is possible to propose that ‘terrorism’ is simply a product of dominant discourse that is true within a particular set of conversations. Clusters of actors cling to their own truths, whilst pointing fingers at the transgressions of the ‘other’. In this way, then, a relativist dilemma is created with respect to the claim that is being examined, bolstered, as ever, by insistent struggles for power.