Why do people keep electing mentally abnormal people as country leaders?

Part of it is the self-selection bias, where people that end up pursuing leadership positions are often driven by the dark triad of personality traits - psychopathy, narcissism, and Machiavellianism. They pursue power for the sake of having power, rather than using it as a tool for the betterment of all people.

Another part of it is the support such people get from other power-hungry people. Wealthy donors, corporate lobbyists, and special-interest groups target people like these because they're incredibly susceptible to corruption. The powerful learn to collude with each other because it's their best bet on retaining or even increasing such power. It gives them a leg up on the competition.

The last part is simply the desperation of the people, who would rather choose one of these sociopathic leaders because they're seen as strong and feel that such leaders would steamroll anyone in their path on the way to get results. They're not bound by things like respect or compassion or honesty AKA normal human traits.

Character matters, and if no good character candidate runs, then I won't vote. I think it's time we let go of the 'better of two evils' fallacy and make our leaders earn our support