Sentence:  If 'left-winger' and 'right-winger' are terms of opprobrium moreover, the journalists can help their chosen cause by invoking <WSD>lateralist</WSD> terms to characterise, in the guise of simply describing, one of the parties in a dispute. This implies that the other party is 'centrist' or 'moderate' or 'non-extremist.' 
Meaning of the word marked with <WSD> tags:  Characteristic of lateralism; pertaining to the interactions of opposing interests of equal power.