Fault is not constant-sum proposition. There’s always plenty of responsibility to go around. Therefore, blaming X for something is not the same as even partially exonerating Y for the same thing.
For example, there is no contradiction — not even a tension — between holding the MPs in the Abu Ghraib photos morally (and criminally) responsible for their actions and holding their superiors, all the way up to the President, responsible for allowing and encouraging those actions. To ask whether we should blame Sgt. Frederick or Undersecretary Carbone is to pose a false alternative.
[And if someone can make a case that Pulp Fiction contributed to the conditions in which such things could happen, then Quentin Tarentino may be morally at fault as well. That wouldn’t excuse, even partially, either Sgt. Frederick or Undersecretary Carbone.]
The criminal law gets this one right: the presence of inciters, abettors, and co-conspirators to some crime does not exculpate the actual perpetrator of that crime. Nor do social conditions that made the crime more likely to occur. But that doesn’t deny that incitement, abetting, and conspiracy are real concepts, or that social conditions can influence crime rates. (The civil law, with its “comparative negligence,” gets this principle wrong; unfortunately, it’s tort-lawyer thinking that dominates current debates.)
To take another current example:
Overeating is a bad, unhealthy habit. People who overeat (including the undersigned) are fully responsible for their behavior.
Encouraging other people to engage in unhealthy behavior is wrong. The peddlers of junk food are fully responsible for their behavior.
Contemporary U.S. culture encourages overeating and under-exercising, and consequently we face an epidemic of obesity. Sociologists, social psychologists, economists, and cultural critics can and should study the mechanisms by which that operates.
Finding and fixing those mechanisms may be essential means to the end of reducing obesity. But the analysis of social mechanisms does nothing to absolve those who overeat or those who peddle junk food of full moral responsibility for their actions.
There are cases of coercion or deception where one person’s wrongful acts deny another person agency, and therefore clear that person of responsibility. If I spike your pineapple juice with vodka, you aren’t responsible for getting drunk, unless I have a reputation for doing such things that you knew, or should have known. But that’s the exception, not the rule. I offer you a drink in order to seduce you, and you voluntarily take that drink, we’re both fully responsible for what happens next.
Understanding this simple princple would avoid lots of pointless arguments.