Cultures project despised traits onto villains precisely because those traits invert their ideals

Evidence

To a great extent, the precise traits involved are idiosyncratic, but certain undesired traits appear with great frequency in any group of people (Newman, Caldwell, & Griffin, 2000). More generally, it is reasonable to assume that through a complex interaction of historical, ecological, and psychological variables (Cohen, 2001), members of a particular culture will both value and despise certain social and psychological characteristics more than others. Thus, particular traits will be especially likely to be candidates for projection. … A related observation was made by Allport (1954/1979), who noted that people always “paint the villain in the same way – as opposite to the cultural ideal” (p. 387). — John F. Dovidio, Peter Glick, Laurie A. Rudman, On the Nature of Prejudice, 2364