I have already written some songs on the subject of war from the warmonger's point of view (Thieves of Innocence is already published, and A Traitor's Love might well end up on album No 7). I do agree with you alanabit that trying to understand the mentalities we abhor is beneficial - from the point of view that one can better guard against them, or against becoming like them.

Yet there some things I don't find it easy to write about, certainly not from the negative angle: Paedophilia is one such. My brain simply finds the desires of such people inexplicable.

But for the majority of crimes and vices (theft, murder, jealousy, greed, head in sand/"not my concern" etc) I don't think it is too hard to take the part of the evil-doer. That is because I believe that the "monster" is in all of us, and not too deep under the skin either. Indeed, most civilised society depends on people controlling their antisocial drives/urges, and provide rules and laws to that effect.