It appears that you feel comfortable with putting those you don't want to understand into either the insane or evil catagory. Your world is safer that way and you don't have to deal with human failings and then forgiveness for those who have failed you.
You are in fact the one sugar coating the situation when you clump all behavior into 2 catagories. There was/is no evil to exorcise and no insanity to fix or medicate therefore you've left no other options to deal with the situation.
They are people that both react to stress with anger. They needed to be taught a better way to work out issues in their marriage. It was fixable.
The problem, as I see it, is that we so often excuse our wrongdoing by softening its effects, at least in our own minds. That is certainly true of parents who destroy the security of their children--first by fighting and carrying on, then by divorce.
Call it what you prefer, but it's certainly more than a mistake. And I think that in order for people to take the steps necessary to stop their destructive behavior, they need to first admit to themselves how very bad it really is.