That's why Trump's opponents see him as a bad man: a fascist, a Nazi, a racist and a sexist (the Mainstream Media is going to do this non-stop for the next four years). And God knows what else he's going to be portrayed as for his next eight years in office (of course, as Hitler!).
It's also why Clinton's opponents see her as the Hildabeast. A criminal, utterly corrupt, and a pathological liar (which she is, but I don't see her as evil, just a child who throws temper tantrums).
I can't quite remember who said it: "The evil man is the child grown strong." It was someone from hundreds of years ago. It might have been Thomas Hobbes, who also said, "Unnecessary laws are not good laws, but traps for money.”
I guess all of the above is because of our inborn narcissism, which is the tendency of all of us to split things into all-good and all-bad (it's why the incompetent Dubya Shrub talked about "the evil ones" attacking us "for our goodness," showing his complete cluelessness about it instead being a revenge attack based on perceived humiliation – and those who feel they have been humiliated almost always seek revenge, which is an attempt to replace shame with pride).
And then this clown started two unnecessary wars (a complete waste of lives and money) because Saddam Hussein (whom the United States put in power and supported in his war with Iran) was suddenly going to nuke the U.S. because he had suddenly turned into a homicidal maniac! who was obsessed with attacking the U.S. You know – because he was Hitler!, but then, everyone is Hitler!
Shrub was a thousand times worse than Barak Obama, who did nothing but go on vacation and improve his golf game his entire time in office.
Wars can be started by portraying your "enemies" as monsters. In fact, they are always portrayed as monsters slobbering to Kill&Main&Destroy. As George Orwell wrote, “Every war when it comes, or before it comes, is represented not as a war but as an act of self-defense against a homicidal maniac.”
Then of course opponents of the wars have to also be portrayed as monsters who want to destroy the country.
"All you have to do is tell them they are being attacked, and denounce the pacifists for lack of patriotism, and exposing the country to greater danger." Joseph Goebbels, the Nazi minister of propaganda said that.
Individuals can be rational and intelligent but when you get people in crowds - or maybe mobs - the have no brains at all. It's just all feels - vacillating all the time - for them. Childish feels.
Even Hitler! (that half-insane, half-genius master of propaganda) noticed that.