Because of those peoples 'worldly' view of the dimension we live in, their hearts are constantly massaged to truly act wicked and they exercise a lifetime of deceit and ruthlessness against others.
And in the last couple of hundred years thanks to Cecil Rhodes, Illuminati occultists, the Rockefeller's and international bankers, and many other godless men like Karl Marx, and Bush cartel, Clintons, and Obama the occult New World Order has emerged. Evil has lived in this dimension since almost the beginning of the time of mankind.
So either you live your life practicing evil or good.
Biblical based many people live for Satan as their ruler, or live for Jesus Christ's as their ruler. Satanist clearly understand evil and good, using the dark forces not in the light of God. Jehovah followers clearly understand good and evil since they use the bible and live their life always in tribulation to strengthen themselves and their will full motivation to serve and follow Gods laws and holly principals, and have the holy spirit in their life. The people who choose darkness are deceived to believe they will live forever in a topic spiritual dimension. The bible is clear evil can not live in truth and in Gods holly heavens, and when they die their spirit will be jailed and tormented forever by the very dark rulers who deceived them in hell.
Mankind is in the end of an age where evil even exists in this earthly dimension. The shaking out of good and the crap is necessary for God to fairly judge and punish evil partakers.
What's next is 1000 years of joy, love and peace ruled by Jesus Christ...and not interfered with by evil.