To me there's no difference between stealing in Haven&Hearth and jacking some NPC's car in Grand Theft Auto. This is in fact a ROLE playing game, which means people can play the role of a thief without being one IRL. The black skills exist to support players who want to play such a role, and protecting yourself against such players is an important part of the gameplay for everyone. If you can't deal with that then go play Farmville instead.
Before you think I'm trying to justify myself here, I've stolen exactly 0 items in this game, and my aim for my character is to be a ranger. Just punishment is as much a part of the game as crime.
I also absolutely do not condone griefing. If you're doing crime just to annoy people IRL rather than improve your characters position, you're no longer playing the game, just being an asshole. Unfortunately, putting up with a certain amount of griefing is a price we have to pay for having a game with as much freedom as Haven & Hearth.
Once a man has changed the relationship between himself and his environment, he cannot return to the blissful ignorance he left. Motion, of necessity, involves a change in perspective.
-Commissioner Pravin Lal, "A Social History of Planet"