The Tokyo fire raids actually killed more people than either Atom Bomb. Japan would have been subjected to these constant raids until they surrendered, whether they surrendered or not. It's very easy to conclude the bombs saved lives.
Terror bombing, strangely, was almost entirely ineffective, outside of the atom bombs. It didn't work against England, or Germany, and wasn't convincing the Japanese they should surrender either. It's unclear whether Japan would have surrendered anyway shortly thereafter. They were completely beaten. Some speculate the Soviet Union backstabbing them had as much or more to do with them surrendering. Either way, they were done.
The problem with saying the deserved it is you treat a whole group of people as one. Japan as a country did, of course, since they were horribly cruel, and incredibly stupid and inept. The idiots had no idea how to win the war even when they started it, and their main military leader said he'd have a free rein for six months, but after that, it was going to get bad. They figured the Americans would decide it was just easier to let the Japs keep what they took then kick them out. Again, they knew they couldn't win. They didn't have any plan to. America wasn't going to let them off after Pearl Harbor, and the atrocities their military committed.
But, having said that, so many people that never wanted war were killed with all those raids. They had no idea why they needed to be in China (which is the base cause for the Eastern Conflict), but certainly could not speak out against their autocratic government.
Japan even backstabbed the Germans. During the 1941 invasion of Russia, as the brutal winter set in, the Japanese signed a non-aggression pact with the Soviet Union, which allowed the latter to transfer massive troops from the far east to launch the infamous counter-offensive of the winter of 1941. Why? Who knows? Germany was their only hope of winning the war, they had no idea how to do it, and were a puny, weak country. So, their leaders were cruel, backstabbing, and incredibly stupid, and got what they deserved. But, the people? Their leadership let them down so badly. It's a pity.