Just came across this brilliant post via a comment thread at SlateStarCodex: The Copenhagen Interpretation of Ethics.
The Copenhagen Interpretation of Ethics says that when you observe or interact with a problem in any way, you can be blamed for it. At the very least, you are to blame for not doing more. Even if you don’t make the problem worse, even if you make it slightly better, the ethical burden of the problem falls on you as soon as you observe it. In particular, if you interact with a problem and benefit from it, you are a complete monster. I don’t subscribe to this school of thought, but it seems pretty popular.
This is dead on right, and once you know to look for it, you see it everywhere.