Maybe eventually. Maybe not. Countries in the process of losing a war often adopt draconian measures towards "defeatist" speech or actions. As for post-war, I think it's quite possible that stories about the firebombing didn't circulate, although they were free to do so (consider the attitude towards atomic bomb victims, for example). An ambivalent attitude towards the firebombings and their victims wouldn't surprise me at all -- similar things have happened in many other countries, after all.
Kisshomaru talks about this a little bit in "Aikido Ichiro". They had a pretty good idea of what was really happening in the war due to their military connections.
You're right about the "defeatist" speech with regards to the general populace, though.