In his classic article on Assyrian ideology and propaganda he explains the rationale for ideology:
In the case of imperialism it [ideology] has the aim of bringing about the exploitation of man by man, by providing the motivation to receive the situation of inequality as "right", as based on qualitative differences, as entrusted to the "right" people for the good of all. (Mario Liverani, "The Ideology of the Assyrian Empire," in Power and Propaganda, ed. Mogens Trolle Larsen [Copenhagen: Akademisk Forlag, 1979], 298.)One might be inclined to think, as many of my colleagues see to, that purveyors of ideology and the propaganda associated with it are simply cynically concocting and promoting it for their own selfish reasons, as a justification to the benighted subjects for their exploitation. Liverani, however, points out that such is a mistake. The ideology is for the exploiters to justify their exploitation to themselves:
The authors of the ideology and beneficiaries of the imperialism (i.e., the Assyrian ruling class), also need to be ideologically motivated. It is not that they do not have sufficient motivation in terms of power and economic benefits (they are the only ones to have them). . . . What I mean by this is that an effective, victorious, enduring imperialism is generally a self-convinced and even fanatical imperialism. It is anything by an ordinary criminal set-up deliberately prompted merely by practical motives. (Liverani, "The Ideology of the Assyrian Empire," 299.)So, in an empire that seizes and exploits the resources of others, the exploiters fanatically believe they are justified in their exploitation.