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If a fictional definition was mentioned once in a series, that doesn't automatically make it a neologism. The authors, in the context of Sheldon, simply emphasized that any such "belief" (which you refer to) is mere empty talk.

and harbored considerable resentment and a desire for revenge against those whose opinions differ from the truth.

It's counterproductive to be angry at the whole world. And to fail to notice, among those you're angry at, that it's yourself... Or does egocentrism prevent you from doing so? :D