What's somewhat puzzling is that Churchill himself knew what the reaction would be to any sort of aerial attack on cities, because in 1938 he said that in a future war British cities would be attacked by bombing, and that the response would be that all men would want to join the fight because they would be so incensed by this cowardly manner of attack. Which is a very natural response: when something drops on you from the air and blows up a bunch of buildings and kills people in their sleep, the reaction is going to be rage, confusion, and a search for something to destroy in retaliation.