This is necessary since in the real world throughout history, all human beings justify their deeds as the right thing and the opponent's as villainous.
Stories were generally moralistic in tone, with long-suffering heroines finally achieving happiness, while villainous relatives or girls who were liars, cheats and bullies received their comeuppance.
Wrestlers portrayed either a villainous or fan favorite gimmick as they followed a series of events which generally built tension, leading to a wrestling match.