This is a brilliant lecture on Evil by Terry Eagleton that really helped me to clarify my own thinking on this. I don't know if he knows it or not but this is also very consistent with Buddhist thought
However, this could be a bit difficult to process without certain background knowledge, especially his idea of demonic and angelic evil. Here is an example that I believe illustrates it
Consider three people, all recently divorced from a long and wonderful marriage that somehow went horribly off the rails.
Person 1 is angry and bitter and now believes that all marriages are a sham. He does not believe that anyone has a happy marriage and if someone is pretending to have one he attacks that person viciously, to their face or behind their back, to prove that he is right. Since he could not sustain a happy marriage, no one can, and anyone pretending to deserves to be destroyed. Furthermore the whole idea of marriage should be thrown out as a contemptible lie. This is my example of the demonic evil Eagleton refers to
Person 2 is also angry and bitter but he blames his former spouse for the demise of the marriage, and possibly also himself. However, now he has seen the light and understand that the marriage failed because they did not follow all the rules. Next time he will get it right. He now advocates a very traditional, conservative view of marriage and people who do not agree are ignorant and morally corrupt. He knows marriage is good because he experienced it as good, but it failed. Rules and enforcement of the rules are needed to protect and enforce what is good. This is my example of the angelic evil that Eagleton refers to. This concept is trickier because people generally view protecting the good as moral. However, when the protection destroys what it is meant to protect by strangling the life out of it, it is evil dressed up as good.
Person 3 believes in dependent co-arising and understands that it is not easy in this world to create something good. He appreciates and is thankful for the good part of his marriage but he understands that the fragile web of interaction that held it together had run its course. Nobody is to blame, it is cause and effect that causes some people to have long stable marriages and others not to, and most of that is beyond our control. This is the good, as I understand it, the creation of compassion and meaning (in my view the two cannot be separated).
This is very consistent with the Buddhist idea of impermanence. All things arise temporarily through cause and effect. This is called dependent co-arising. In Buddhism, evil is created through ignorance and, as we can see from the examples above, not understanding the impermanent nature of things has this result. For demonic evil the problem lies in rejecting anything that is found not to be permanent, leading to the destruction of things that are good and inevitably impermanent. Angelic evil involves killing something that is good by trying to force it to be permanent when it is not. Th Buddhist way is the middle way, trying to create good while understanding its transient nature