What causes evil?

What causes mental illness, power, and greed in human beings? Why do some humans have mental illness, and Tribalism, whether it is a religion, or whether it is simply just a bully? While I am not saying that this exactly is because of Hitler, Osama bin Laden, Communism, Regime, Terrorism, Saddam Hussein, Mao Zhedong, or Fidel Castro during The Cuban Missile Crisis, or in this year because of COVID-19 The Chinese Communist Party, and Xi Jinping, or people from a few years back like “Parkland,” and other terrible tragedies to happen society? I am asking this because as my other few questions asked why do humans do bad things to harm lives? Why do humans exploit mental illness, power, and greed instead of Loving, and Caring for Others? How could Hitler take over The World with Nazi, Germany out of mental illness, or how did this year Communist China infect us all with a virus Global pandemic that killed over 2 million, and counting Worldwide as the numbers keep growing? Why can’t humans beings learn how to love each other why can’t we all have biblical love like Jesus Christ love you who for gave you of your sins why can’t we have good people everywhere in all countries with one universal circular language barrier where we all love each other? What causes sin? Why can’t we have no Countries? 
Why does God allow dictatorship like 
The USSR? Why do humans think Christianity is false when it’s not like rebelling David Grisham those YouTube videos in Alaska as humans rebelled him?

2017-04-11T00:37:33.809Z