It's not surprising that people on the far Left deny that evil exists.
The problem is, we've rebranded evil and demonic activity as *mental illness* for far too many people.
I'm NOT saying all mental illness is demonic activity, I recognize there is legitimate cases of it.
I hate that I have to put that disclaimer out even here on FR but I know someone will shred me for it otherwise.
If someone has turned their backs on God and hates Him that much, and turns that evil, chances are it's NOT a true mental illness issue.
You cannot reject God and think you'll be OK. SOMETHING will always come in to fill the void.
At one time the DSM manual defined homosexuality as a mental illness.