Psychopaths. One needs to be that in order to viciously pursue personal power over all those around you in an unquenchable manner. They have no conscience, zero empathy and zero remorse. I read an article decades ago that the majority of highly successful people are, in fact, psychopaths in a mildly benign form. The more aggressive types seek even greater power and they band together because they recognize that quality in each other. Advanced forms of psychopathy are the only traits they respect and admire. The character in Silence of the Lambs is simply a less effective form of them.