Drawing a distinction between blameworthiness and foolishness

Reading various 9/11 retrospectives reminds me of a curious thing that happened after the attacks: some people, typically leftists of some stripe, would say that the attacks were "our fault", and then a whole bunch of people would angrily respond, no, it was the terrorists fault. But I think this sort of exchange shows that a distinction was not being made between blameworthiness and foolishness.

If a man gets mugged in a dangerous neighborhood in the middle of the night, we sometimes say that it was "his own fault" because he should have known that there was a good chance of getting mugged. But this is not to imply that the man is morally blameworthy for the crime--of course, it is the mugger who is blameworthy in this sense. What we are more accurately faulting the man with is having poor judgment--of being foolish enough to venture out into a dangerous neighborhood in the middle of the night.

And so I think when people say, "9/11 was our fault" or "we brought it on ourselves", what they really mean is that our foreign policy was foolish because it put America in a dangerous position. I'm pretty sure they would agree that the moral blame for the attacks rests with the people who actually carried them out.