The Bomber Command attacks on German cities, coupled with precision attacks on V-weapon sites and other infrastructure were undoubtedly viewed by allied leaders as an important contribution to ending the war in Europe - the only real aim. Why else would they begin assembling Tiger Force consisting of 22 squadrons of Lancaster/Lincoln/Liberator bombers with the clear intention of doing exactly the same thing to Japan?
The only people responsible for the millions of deaths during WWII were Hitler and his acolytes, along with their counterparts in Japan.