So........the attacks on 9/11 were justified because we had been systematically wiping out all muslims and bombing their cities to ruble, enslaving them by the millions in death camps and were well on our way to bombing the entire world in order to rule everyone?
Is that the justification for 9/11?
See post 53 on the error of terror bombing - it may have cost the British the Battle for France. The point is that if terror bombing enemy civilians is ok for the U.S. to do, the enemy, now or in the future, may decide that terror bombing U.S. civilians is ok for them to do also.
Remember what Voltaire said: Beware of persons who can convince you of absurdities, because they can convince you to commit atrocities.
A number of posters here are trying to convince others of the absurdity that targeting civilian women and children with terror bombing is ok. In my opinion - it is not ok for Al Quada to do terror bombing to us, or for us to do to others, as in Dresden.