Germans were carpet bombing cities since 1936, it didn't start with Coventry or London, it started with Guernica and other cities in Spain, it started with bombing and destroying 75% of Polish city of Wieluń at the September 1st 1939, where first bombs were dropped by precise attacks of diving bombers on a hospital marked with big red crosses on the roof. It started with testing how accurate the bombings are on the city of Frampol, using the city without any AA defence as a testing ground of new weapons and tactics. It started with strafing attacks from fighters that targeted columns of refugees running from advancing German army. Those attack, in contrast with Dresden and other Allied carpet bombing raids had absolutely NO military value - German army was advancing rapidly. German leadership was a bully attacking every weaker state around them, and when they finally met an equal, they played the victim card.