Therefore, killing others because they were attempting to "pollute our society" (disregarding the ambiguity of this statement) is not universally justified.
Also, in its ambiguity, Old Hickory's argument fails to acknowledge that the people who were bombed in the Hiroshima attacks were not those who sought to bring down the other nations. They were, in fact, innocent civilians who had no part in WW2, did not capture and torture Allied soldiers, etc.
So how did dropping a bomb on *them* stop their leaders?
Punishing the whole is not an adequate way to deter the few.
The same can be said for Sept 11. We would accept no such justification which suggested that this event was moral on the part of the terrorists who did it because they objected to the government's foreign policy. Even if this objection is warranted, we morally condemn the response to it, as many innocent victims resulted from this displeasure with the authority.