I do not agree that typical Japanese civilians deserved "what they got".
I would say the same thing about most civilian populations in a war.
However, US forces were faced with increasingly fanatical, suicidal,
opposition from Japanese forces the closer they moved toward the
Japanese main islands.
The Japanese navy, at this time, was all but nonexistent. After Okinawa
the Japanese air force was also all but annihilated after three days of
Kamikaze attacks. On Okinawa a large number of civilians committed
suicide.
All indications were that any attempt to invade the home islands would
be a bloodbath of epic proportions. There was no indication of the
Japanese considering surrender. Civilians, POW's, and allied service
personnel were still being brutalised and murdered by Japanese forces
all over SE Asia, China and Korea.
Dropping the first bomb was an inevitable outcome of these considerations.
The Japanese did not surrender even after the first bomb.
Also note that conventional bombing and napalm was killing upwards
of 100,000 per night in any case and the Japanese would not surrender.
Hirohito was kept alive, despite deserving to fall through a hole in the
floor with a rope round his neck, to minimise the on-going potential risk
of a civil uprising and/or mass suicide. The allies had had enough of death.
