Sometimes some people are “mental” and sometimes just evil.
When I was much younger I never thought I would see true evil in my lifetime. But in the last three decades at least, I’ve seen things that I think were expressions of true evil; something akin to a loss, an absence of that one spark from which grace might be possible.
I don’t know when you grew up, but I’m guessing you weren’t paying attention. There has always been true evil and there a many obvious times in our past that evil was far more overt then it is today.