more on dresden

The bombing of Dresden was one of the most evil acts perpetrated by the Allies during World War II. As Simon Jenkins notes in "Time to Say We're Sorry":

Attitudes to the Dresden bombing, have undergone many shifts over time. Immediately after the attack there was widespread revulsion. Winston Churchill, who had ordered the raid to appease Stalin, was sufficiently shocked by the reaction to question the policy of "bombing German cities simply for the sake of increasing the terror." He referred to the bombings as "mere acts of terror and wanton destruction, however impressive." The Americans likewise distanced themselves from avowedly "terrorist" air attacks, after their own planes had gunned down people fleeing the burning city the morning after the British raid.

Great evil can be committed by the good guys even in a justified war, another reason to avoid wars in general.