If you don't ever call anything evil, you also lose the power to present anything as "Good."
Agreed.
For example, if I refuse to call a serial killer 'evil' and just write what he did, I also lose the ability to call the detecitive who caught him a 'good' person, as all I can do is present the facts.
Exactly.
I would also technically lose the ability to say what happened to the victims was 'bad'.
You're getting the hang of this :)
I know wiki is supposed to have a NPOV, but that doesn mean that it has to lack moral judgement as well.
I think we should refrain from explicit moral judgment as much as we can. Here's an example of an edit I made in that spirit:
http://en.wikipedia.org/w/index.php?title=Margrethe_II_of_Denmark&diff=1...
Queen Margrethe is a chain smoker. Whether that is a good thing or a bad thing or neither is none of Wikipedia's business.
Regards, Haukur