So, it is justified to kill innocent civilians? Pearl Harbor was an attack on the military. Nagasaki and Hiroshima were attacks on civilians with radioactive half-life that caused diseases and genetic defects for hundreds of thousands in the aftermath. If it's alright in your book to kill civilians, then you shouldn't have any problem with what terrorists do.
The war in Europe had ended months before the nukes were dropped in Nagasaki and Hiroshima. The Germans had already surrendered. The idea that the nukes saved any lives at all is complete propagandist bullshit.