Why do psychopaths and narcissists get elected?

A theory.

In a word, Confusion.

To elaborate,

The electorate misinterprets the false confidence of the narcissist, and psychopath for the natural confidence that is the product of Competence.

The masses, select leaders based upon the perceived competence.

If a psychopath , or a narcissist can successfully disguise their true malevolent nature, the public can often be deceived into believing the Psychopath and or Narcissist is a Competent individual.

This is why public debates between candidates is crucial in a democratic system.

A free open debate is much like a duel , in that it places candidates in a public, highly stressful competitive situation. A situation which allows the public to see glimpses of the actual character and competence of the candidates.

False confidence is generally exposed in those type of situations. Along with malevolent natures.

Which is a primary reason a narcissist will avoid an honest debate.

The narcissist lacks competence, and resorts to combative attempts to gaslight.

The lack of substance is exposed, the lack of competence is revealed.

Which generally results in irrational angry responses.

This allows the public to choose between competent leaders and incompetent individuals.

Generally , the majority will prefer truth over lies, competence over delusion.

That's the inherent hope in the democratic process anyway.