This makes good sense.
I think the problem is that "evil" doesn't have a productive meaning anymore because it is enmeshed in that moral relativism/absolutism business.
It's personal. Getting mad at evilness has no meaning. You get mad at the person who made a choice to hurt/violate you regardless of the reason.
And still I'm left wondering when compassion plays its role and to what extent? After or along with the surprised and unforced forgiveness?
I don't have an answer, but I think that our collective understanding of compassion has suffered from a incomplete transmission (or perhaps incomplete adoption) of the Buddhist understanding of compassion. This isn't to say that Buddhism has any lock on compassion, just that the way we talk about compassion has been strongly influenced by the globalization of Buddhism since WW II.
These thoughts by Pema Chodron may be useful in considering what compassion is and how it plays its role, either healthily or otherwise:
Student: I'm interested in the idea of idiot compassion that was in Ken McLeod's book [Wake Up To Your Life]", and wishing compassion for someone who's doing harm to you or that you need to remove yourself from. How do you differentiate the feeling of compassion and the need to remove yourself from a damaging situation?
Pema: Idiot compassion is a great expression, which was actually coined by Trungpa Rinpoche. It refers to something we all do a lot of and call it compassion. In some ways, it's whats called enabling. It's the general tendency to give people what they want because you can't bear to see them suffering. Basically, you're not giving them what they need. You're trying to get away from your feeling of I can't bear to see them suffering. In other words, you're doing it for yourself. You're not really doing it for them.
These by Robert Masters are useful as well:
… ‘When those who espouse idiot compassion encounter offensive behavior from others, they usually take pains to not only be nonjudgmental (or at least not to say or do anything that could be construed as judgmental), but also to examine whatever such behavior may be triggering in them, while bringing no significant heat to those who are actually behaving offensively. That is, if what you are doing is upsetting me, my job (as a graduate of Idiot Compassion 101) is not to focus to any significant degree on your behavior, but rather to find out what my being bothered says about me, while perhaps also acknowledging and appreciating the opportunity you are giving me to examine myself.
This is not only a misguided reading of the art of allowing all things to serve our awakening, but also a far-from-compassionate response to our offending others, for we, in not being on the side of doing what we can to bring them face to face with the consequences of their actions, are on the side of depriving them of something they may sorely need. And in letting them off the hook, we are doing the same for ourselves.'
Sometimes, compassion is gentle. At other times, genuine compassion looks like this:
Knowing which face to show on any particular occasion is wisdom. Doing so is skillful means.
Or, as Hippocrates put it: "Life is short, [the] art long, opportunity fleeting, experiment treacherous, judgment difficult. The physician must not only be prepared to do what is right himself, but also to make the patient, the attendants, and externals cooperate."
A tall order indeed.