Dunno, doesn't seem much different from explaining that you're not an evil person, your genes and current programming made you do it, and that you can both let it go -- and feel better -- AND change your programming so that you don't do similar things in the future.

Religion doesn't have a monopoly on forgiveness, after all. In order for it to work, there has to be something there in the brain that supports that function. And nothing stops rationalists from using that same mechanism. Hell, it's a critical part of a set of techniques I teach for altering one kind of "self-esteem".

Now, the idea that there's somebody who loves you no matter what, that might still be attractive. But if everybody learns at a young enough age how to use forgiveness and other methods to address their broken beliefs and judgments, they should already be in the habit of doing that.

Of course, good luck trying to teach forgiveness in schools... Religious folks will positively freak about that, because they DO think they've got a monopoly on the process.