this is such a fantastic and reassuring response
I think it's a consequence of viewing good and evil as inherent character traits or moral natures that people can have rather than a series of independent moral decisions.
In that framework, a "good person" committing a good action or a "bad person" committing a bad action are not seen as moral actions that affect one's opinion of the person; they are simply seen as the person acting in accord with their supposed moral nature. On the other hand, a "good person" committing a bad action or a "bad person" committing a good action are seen as moral actions and do affect one's opinion of that person, because they are acting against their supposed moral nature. So in a twisted way, "good people" are only given credit for their bad actions and "bad people" are only given credit for their good actions.
And unfortunately we see this way of thinking extended from fictional characters to real world politics.
