Past societies never had any problem about the existence of purposive evil - intentional evil; this was seen among humans and rooted in the demonic.
But the intellectual elite of Western societies long ago began to discard the concept of demonic evil, and soon after discarded the whole idea of purposive evil, since there was nowhere for evil to be located.
Without the reality of the demonic, to call something evil just becomes a matter of opinion, perhaps a matter of rhetoric.
The point is that to discard the concept of purposive evil is not in any sense sense to disprove it.
To find talk of devils and demons to be childish and embarrassing is not in any sense to refute thousands of years of testimony from the greatest of human minds (including the holiest of human minds).
And suppose that there really is purposive evil at work in the world, yet we refuse to acknowledge its reality?
(After all, human ingenuity can always find other ways to explain reality, leaving out any particular causal variable.)
Well, the obvious consequence is that evil would then be unstoppable.
Bad things might be observed, we might have theories about why these bad things were happening, and these theories might lead to action intended to be remedial - but the bad things would continue because we were not addressing the real cause.
But how would we know that purposive evil was at work? Well, answering that is at least as hard as answering any question about motivations and intentions.
Yet, operating on the assumption that there are no purposive evil intentions is already implicitly to claim that we know that there is no purposive evil.
The way to proceed is to acknowledge and accept the vast consensus of human history that there really is such a thing as purposive evil.
We can then try to understand the nature of purposive evil - about which there is much less consensus, and also discern whether or not purposive evil is operative in any specific situation.
Purposive evil can of course be overused as an explanation of human affairs, it can be misunderstood, it can be deceptively manipulated.
But so can evolutionary theory, so can economics - these are presumably real explanations for human affairs, but they are hard to understand, their specific relevance needs to be examined, they are open to misuse.
The point is that our society is displaying the most extraordinary and extreme arrogance in not just disregarding but deriding the concept of purposive evil and its roots in an unseen reality of 'the demonic'. This is historically unprecedented. If our society is mistaken about this, then presumably we would expect the consequences to be extremely severe.