There was no national television.
Japan was defeated with the Atomic Bomb...and the 1000's of B-29s that preceded it.
Oh, and the US Navy and Marine Corps.
I’m pretty sure they had radio and newspaper. Propaganda is a big part of war. If anything can be done to deplete morale, so be it. Nukes are pretty good at doing just that. Nothing depletes morale like watching half your homeland turn to radioactive ash. If it’s a religious focal point for the enemy, even better.