Differentiate means to distinguish or know the difference. If god allows us to know what is good or what is (not good) evil - how do we know god is good or evil? Well, if god allows us to know the difference in good and evil - it's pretty simple. If god is evil He allowed us to know. Actually nobody with any sense believes that crap!
What most people define as evil is insanity, and the media helps promote these ignorant misconceptions. They know that people are not demon possessed. Any psychologist worth a damn knows that there are psychopaths capable of incredible evil. They also know that there are no resources to identify these dangerous people or to get them out of society until they have done great many ghastly things. Since the 80's when Reagan threw the mentally ill onto the streets this has been a growing problem.
There are people who should be held accountable for not providing the funds for mental health and to get dangerous people out of society. They also don't know what kind of insane people are entering this country. Instead of trying to make us safe they are using a buzzword (evil) to create hysteria and stampede the ignorant hillbillies into their fanatic domes.
You never hear them call a corporation evil - they just do their evil bidding.